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Aviation: questions and answers
The most searched questions about Aviation, with a direct answer, an explanation and sources.
Physics of flight
How does a plane stay in the air?
A plane stays in the air as long as four forces stay in balance: lift from the wings opposes weight, and thrust from the engines opposes drag. In level… more…
Physics of flight
Why do planes vibrate on takeoff?
Most takeoff vibration comes from the runway, not the aircraft: tyres rolling over expansion joints and grooved pavement at 250 km/h (135 kn) shake the whole… more…
Military aviation
Why do aircraft carriers float?
An aircraft carrier floats because its steel hull encloses a huge volume that is mostly air, so its average density is far below that of seawater. By… more…
Physics of flight
Why does an airplane fly?
An airplane flies because its wings turn the oncoming airflow downward, and the air pushes back with an upward force called lift. The wing's shape and angle… more…
Commercial aviation
How much does the 737 max 8 cost?
Boeing's last published price list, in 2019, put the 737 MAX 8 at $121.6 million. The figure no longer means much: Boeing publishes no list prices now, and… more…
Physics of flight
Why do planes require airplane mode?
Airplane mode is required because a phone hunting for a distant ground tower transmits at full power, and regulators like the FCC and EASA want to rule out… more…
Physics of flight
How far can the b 21 fly?
The B-21 Raider's range is classified: neither the US Air Force nor Northrop Grumman has published a figure (data of September 2026). The Air Force describes… more…
Physics of flight
Why do airplanes fly so high?
Airliners cruise at 9–12 km (30,000–40,000 ft) mainly to save fuel: the air up there is a third to a quarter as dense as at sea level, so drag falls and jet… more…
Commercial aviation
Why is the a320 so loud?
The whistle is not the engines. A320s built before 2014 have small fuel overpressure vents under each wing that behave like a blown bottle, emitting a pure… more…
Military aviation
How much the air force pay?
The US Air Force pays by rank and years of service under the common military pay table: a new airman (E-1) earns about $2,320 per month in basic pay and a… more…
Physics of flight
Why does the speed of sound change with altitude?
The speed of sound changes with altitude because it depends on air temperature, and temperature falls as you climb through the troposphere. Colder molecules… more…
Physics of flight
Why does a plane keep circling?
A circling aircraft is usually holding: air traffic control has asked it to fly a racetrack pattern while a runway, a weather cell or a traffic gap clears… more…
Commercial aviation
Why is the a320 so popular?
Because it made narrowbody flying cheap to operate and cheap to staff. The A320 family has taken more than 18,000 orders since 1984, on the strength of… more…
Commercial aviation
Why do private jets fly higher?
Business jets are certified for higher ceilings than most airliners, typically 13,700 to 15,500 m (45,000-51,000 ft), because their light wing loading and… more…
Commercial aviation
What does the airbus a380 weigh?
The A380-800 is certified to a maximum take-off weight of 575 tonnes (1,268,000 lb), the highest of any airliner. Empty it weighs about 277 tonnes, and it may… more…
Military aviation
Why is the rafale so popular?
The Rafale sells because it is a proven, independent multirole fighter: one airframe handles air defence, strike, reconnaissance, carrier operations and… more…
Commercial aviation
What does commercial flights mean?
A commercial flight is any flight operated for payment, carrying passengers, cargo or mail for hire or reward. Regulators call this commercial air transport… more…
Commercial aviation
How much does the a320 cost?
Airbus stopped publishing list prices in 2018. In that final catalogue the A320neo was $110.6 million, the outgoing A320ceo $101.0 million and the A321neo… more…
Physics of flight
Why are supersonic planes banned?
Supersonic aircraft are not banned; what is prohibited is civil supersonic flight over land in the United States (since 1973) and many other countries… more…
Physics of flight
What are supersonic planes?
Supersonic planes are aircraft that fly faster than the speed of sound, above Mach 1, about 1,060 km/h (573 kn) at cruise altitude. Most are military… more…
Military aviation
What is the mig 29 equivalent to?
The MiG-29 is the Soviet counterpart of the American F-16 Fighting Falcon and, in size and twin-engine layout, of the F/A-18 Hornet: a light, agile… more…
Physics of flight
Why do planes dump fuel?
Planes dump fuel only when they must land while still heavier than their maximum landing weight, usually after an engine problem or a medical emergency… more…
Military aviation
How high can the mig 29 fly?
The MiG-29 has a service ceiling of about 18,000 m (59,000 ft), higher than the F-16's roughly 15,000 m (50,000 ft). That figure is for a clean aircraft at… more…
Physics of flight
Why are supersonic planes coming back?
Supersonic airliners are returning because three obstacles are easing: the overland boom ban, which the United States moved in 2025 to replace with a noise… more…
Physics of flight
Why do planes use knots?
Aviation uses knots because a knot is one nautical mile per hour, and a nautical mile equals one minute of latitude on a chart. That link between speed… more…
Commercial aviation
Why is the boeing 747 being retired?
Mainly economics. Two modern engines burn less fuel than four and, thanks to ETOPS rules, twins like the 777 and 787 may now fly the same long oceanic routes… more…
Military aviation
Why was the mig 29 made?
The MiG-29 was built to give Soviet frontal aviation a light, agile fighter able to win air superiority over the battlefield against the American F-15 and… more…
Military aviation
How much does the rafale weight?
A Rafale weighs about 10 t (22,000 lb) empty in the single-seat C version, roughly 10.6 t for the carrier-borne Rafale M with its strengthened landing gear… more…
Military aviation
How much does the mig 29 weight?
A MiG-29 weighs about 11,000 kg (24,250 lb) empty, around 15,000 kg (33,000 lb) at normal take-off weight with internal fuel and air-to-air missiles, and up… more…
Military aviation
Why is the rafale so slow?
The Rafale is not slow: it reaches Mach 1.8 (about 1,915 km/h, 1,035 kn) at altitude and can supercruise near Mach 1.4 with a light load. It does give up the… more…
Military aviation
Why is the mig 29 called fulcrum?
“Fulcrum” is not the MiG-29’s Soviet name but a NATO reporting name assigned by the Air Standardization Coordinating Committee around 1979. Fighters received… more…
Physics of flight
Why do planes zig zag?
Airliners rarely fly perfectly straight because they follow published airways and waypoints, deviate around thunderstorms and turbulence, and are vectored by… more…
Physics of flight
Why do contrails form?
Contrails form when hot, humid exhaust from jet engines meets air that is cold enough, typically below about −40 °C at cruise altitude, for the water vapour… more…
Physics of flight
Why is the speed of sound so slow?
Sound is slow because it is a push, not a signal: air molecules must bump into their neighbours to pass the pressure wave along, and they do so at roughly… more…
Physics of flight
What happens when a plane goes supersonic?
When an aircraft passes Mach 1 the air can no longer move out of its way in advance, so pressure disturbances pile up into shock waves at the nose, wings and… more…
Commercial aviation
How far can the 737 max fly?
Between roughly 3,100 and 3,800 nautical miles (5,740-7,040 km) depending on the variant. Boeing quotes 3,550 nmi (6,570 km) for the 737 MAX 8, 3,800 nmi… more…
Commercial aviation
Why is the 737 max 7 not certified?
The MAX 7 is waiting on one specific fix: its CFM LEAP-1B inlet can overheat if engine anti-ice is left on in dry air, a hazard the FAA now limits in service… more…
Physics of flight
How much is the sound barrier?
The sound barrier is not a price or a quantity: it is the speed of sound, which an aircraft meets at Mach 1. That speed is about 343 m/s (1,235 km/h, 667 kn)… more…
Physics of flight
Why is the sound barrier?
There is no physical wall in the air: the sound barrier is the sharp rise in drag and loss of control that early aircraft met near Mach 1, when shock waves… more…
Physics of flight
Why does the sound barrier exist?
The sound barrier exists because pressure disturbances travel through air at the speed of sound. Below Mach 1 the air ahead of an aircraft receives warning… more…
Physics of flight
How do supersonic planes work?
A supersonic aircraft is built to live with shock waves. Thin, sharply swept or delta wings and a slender fuselage keep wave drag low; intakes with movable… more…
Physics of flight
How high planes fly?
Commercial jets typically cruise between 9,000 and 12,500 m (30,000–41,000 ft), where thin air cuts drag and fuel burn while the engines still get enough… more…
Physics of flight
Are supersonic planes coming back?
Yes, but not yet for passengers. Concorde retired in 2003; since then Boom's XB-1 went supersonic in January 2025, NASA's X-59 flew in October 2025 to test… more…
Physics of flight
Why did supersonic planes stop?
Concorde stopped flying in 2003 because it no longer paid its way: it burned far more fuel per seat than subsonic jets, carried only around 100 passengers… more…
Military aviation
Why are military aircraft grey?
Military aircraft are grey because neutral grey blends best with the sky and haze at the distances where a pilot tries to spot them. Against a bright sky a… more…
Physics of flight
How high do supersonic planes fly?
Supersonic aircraft cruise far higher than airliners. Concorde flew at 15,000 to 18,300 m (50,000 to 60,000 ft) and the SR-71 operated above 24,000 m (80,000… more…
Commercial aviation
What is the airbus a380 800?
The A380-800 is the only version of the Airbus A380 ever built: a four-engine, full-length double-deck widebody, the largest passenger aircraft in airline… more…
Physics of flight
How much the speed of sound?
In air at 20 °C the speed of sound is about 343 m/s, or 1,235 km/h (767 mph, 667 kn). It depends on temperature, not pressure: in the standard atmosphere it… more…
Physics of flight
How does the sound barrier work?
The sound barrier is the sharp rise in drag and control difficulty an aircraft meets as it nears Mach 1, about 1,062 km/h (573 kn) at cruise altitude. Air… more…
Military aviation
What is the b-21?
The B-21 Raider is the US Air Force's next stealth bomber, built by Northrop Grumman to replace the B-1B and B-2 from the late 2020s. A two-crew flying wing… more…
Commercial aviation
Why are commercial flights safer than private?
Because they are two different systems, not two kinds of flying. General aviation in the United States runs at roughly 0.9 fatal accidents per 100,000 flight… more…
Military aviation
Why are fighter jets so loud?
Fighter jets are loud because their engines push a small mass of air out at very high speed, and jet noise rises with roughly the eighth power of exhaust… more…
Physics of flight
Why do planes board front to back?
Most airlines do not board front to back for speed: the premium cabin at the front boards first as a commercial perk, and economy then boards by zones, often… more…
Military aviation
Why is the rafale so good?
The Rafale's reputation rests on an 'omnirole' design: one airframe covering air defence, strike, reconnaissance, nuclear and carrier missions, often within a… more…
Military aviation
How much the air force get paid?
Air Force pay follows the same table as every US service: it depends on rank and years served, not on the branch. In 2025 a brand-new airman (E-1) earned… more…
Military aviation
How much does the rafale cost?
A Rafale costs roughly €75–90 million flyaway for France, but export contracts run to €200–250 million per aircraft once weapons, spares, training and support… more…
Physics of flight
Why does an airplane stay in the air?
An airplane stays airborne because its wings produce lift that matches its weight. Moving through the air, a wing turns the flow downward and creates lower… more…
Military aviation
Why did fighter jets just fly over?
An unexpected fighter flyover is almost always one of four things: a ceremonial pass over a stadium, funeral or holiday event; a training or transit flight… more…
Commercial aviation
Why is the a320 ptu so loud?
That barking is the A320's power transfer unit. The PTU lets the green hydraulic system drive the yellow one, or the reverse, by mechanically coupling a pump… more…
Commercial aviation
How much fuel does the airbus a380 hold?
The A380-800 holds up to 320,000 litres (84,500 US gal) of jet fuel, spread across tanks in the wings, the centre section and the horizontal stabiliser. At a… more…
Physics of flight
Why does the sound barrier boom?
The boom is not the aircraft breaking anything: it is the shock waves that any supersonic aircraft drags behind it, heard as a sudden pressure jump when the… more…
Military aviation
Why are fighter jets flying over my house today?
Fighter jets over a home almost always mean routine training, a transit between bases, a flypast for a public event or, rarely, an air-defence scramble… more…
Physics of flight
Why does the sound barrier break?
The sound barrier is not a physical wall: it is the sharp rise in drag and loss of control that pilots met near the speed of sound (about 1,225 km/h, 661 kn… more…
Commercial aviation
Why do airlines overbook flights?
Because a predictable share of passengers never turn up. Airlines sell a few more seats than the cabin has, using historical no-show rates by route, fare type… more…
Physics of flight
How does a plane fly?
A plane flies by using engine thrust to move its wings through the air fast enough to generate lift greater than or equal to its weight. The wing's shape and… more…
Military aviation
Why is the rafale so expensive?
The Rafale is expensive because France developed it alone, without partners to share more than €40 billion of development cost, builds it at a low rate of two… more…
Military aviation
Why do aircraft carriers have angled decks?
Angled flight decks let a carrier launch and recover aircraft at the same time and give a pilot who misses the arresting wires a clear path to go around. The… more…
Commercial aviation
Why is the 737 max 10 not certified?
It is last in the queue and blocked by problems it did not create. Boeing must first deliver a permanent fix for the LEAP-1B engine anti-ice inlet, an issue… more…
Military aviation
Why are fighter jets flying today?
Fighters fly on most weekdays because training never stops: squadrons must log sorties to stay qualified, and bases publish weekly flying schedules. Busier… more…
Physics of flight
Why do planes need air start?
Most jet engines have no electric starter: the compressor must be spun to around 20-25% of rated speed before fuel is lit and the turbine can sustain itself… more…
Commercial aviation
How fast does the boeing 747 fly?
A Boeing 747 cruises at about Mach 0.85, roughly 900 km/h (490 kn) true airspeed at 35,000 ft (10,700 m). The 747-8 is quoted by Boeing at a typical cruise of… more…
Physics of flight
Why do planes vanish?
Planes vanish from tracking when their transponder and ACARS stop transmitting, through failure, deliberate switch-off or loss of power, while beyond ground… more…
Physics of flight
Why do jet engines use kerosene?
Jet engines burn kerosene because it packs about 43 MJ/kg into a dense, cheap, easy-to-store liquid that stays fluid down to −47 °C (Jet A-1) and does not… more…
Physics of flight
What planes can go supersonic?
Only aircraft designed for it: military fighters and interceptors (F-15, F-16, F-22, F-35, Rafale, Eurofighter Typhoon, Su-57), the B-1B bomber and a handful… more…
Physics of flight
How does the speed of sound change with altitude?
The speed of sound depends only on air temperature, not on pressure or density, so it falls as the troposphere cools: about 340 m/s (661 kn) at sea level in… more…
Physics of flight
How does the speed of sound vary with temperature?
The speed of sound in air rises with the square root of absolute temperature: about 340 m/s (661 kn) at 15 °C at sea level, falling to about 295 m/s (573 kn)… more…
Physics of flight
How far is the sound barrier?
The sound barrier is not a distance but a speed: Mach 1, the local speed of sound, about 1,225 km/h (661 kn) at sea level and 1,062 km/h at 11 km. Airliners… more…
Physics of flight
What are contrails?
Contrails are condensation trails: lines of ice crystals formed when the hot, humid exhaust of a jet engine mixes with air colder than −40 °C. Water vapour… more…
Physics of flight
Why do planes need airplane mode?
Airplane mode is required mainly by regulation and caution, not by a proven history of accidents. Regulators such as the FAA and EASA require devices to stop… more…
Physics of flight
Why does the speed of sound vary with temperature?
Sound is a pressure wave passed along by molecular collisions, so it travels faster when molecules move faster, and molecular speed is set by temperature. In… more…
Physics of flight
Why do jet engines not melt?
Turbine inlet gas can exceed 1,600 °C, above the melting point of the nickel superalloys in the blades, yet they survive because the metal never touches that… more…
Physics of flight
Why do supersonic planes have swept wings?
Sweep delays and softens the drag rise around the speed of sound. Only the airflow component perpendicular to the leading edge counts for compressibility, so… more…
Commercial aviation
How fast does the a320 go?
An Airbus A320 cruises at about Mach 0.78, roughly 830 km/h (450 kn) true airspeed at 35,000 ft (10,700 m). Airbus gives a maximum operating speed of Mach… more…
Commercial aviation
What is the 737 max 8?
The 737 MAX 8 is Boeing's re-engined single-aisle airliner, the best-selling member of the 737 MAX family. It pairs a 737-800 fuselage with CFM LEAP-1B… more…
Commercial aviation
How much does the 737 max cost?
Boeing has not published list prices since 2019. In that final list the 737 MAX 7 was $99.7 million, the MAX 8 $121.6 million, the MAX 9 $128.9 million and… more…
Physics of flight
How far is the speed of sound?
The speed of sound is a speed, not a distance: in air at 20 °C and sea level it is about 343 m/s (1,235 km/h, 667 kn), so sound covers one kilometre in… more…
Military aviation
How many b-21 will be built?
The US Air Force plans to buy at least 100 B-21 Raiders, the official programme of record since it was announced in 2015. Senior Air Force leaders have argued… more…
Physics of flight
How high are contrails?
Contrails usually form between about 8 and 12 km (26,000–40,000 ft), the cruise band of jet airliners, where the air is colder than roughly −40 °C. Below that… more…
Physics of flight
Why do planes just sit in the sky?
Planes never sit still; a cruising airliner covers about 900 km/h (490 kn). It looks motionless because it is far away: at 11 km (36,000 ft) altitude its… more…
Physics of flight
Why do jet engines have a spiral?
The spiral painted on a jet engine's spinner is a safety marking. When the fan is turning, the spiral blurs into a visible, pulsing pattern that warns ground… more…
Physics of flight
How long do contrails last?
Contrails last anywhere from a few seconds to several hours. In dry air at cruise altitude the ice crystals sublimate almost immediately; when the surrounding… more…
Physics of flight
How does the sound barrier break?
The sound barrier is not broken so much as crossed: an aircraft with enough thrust and a shape that tolerates shock waves accelerates through Mach 1. Chuck… more…
Physics of flight
Why do planes vanish in the bermuda triangle?
They do not, at least not more than anywhere else. The US Coast Guard, NOAA and insurers find no higher rate of aircraft or ship losses in the Bermuda… more…
Military aviation
Why was the sr 71 blackbird decommissioned?
The SR-71 was retired in 1990 because the Air Force judged it too expensive to keep flying, at hundreds of millions of dollars a year, when satellites and… more…
Military aviation
Why are military aircraft on flight radar?
Military aircraft appear on flight-tracking sites because many carry the same Mode S and ADS-B transponders as airliners and must broadcast their position… more…