Flying for business or pleasure is one of the most thrilling experiences in the world, but it remains full of mystery for the average traveller. Curious passengers have burning questions every time they step foot on a plane – from whether pilots require a key to start a plane to where flight attendants sleep on long-haul flights. MailOnline Travel spoke to a number of experts to debunk some of the myths that exist and answer some of travellers’ frequently asked questions about planes. Scroll down for video . Once a pilot initiates the sequence to start a modern plane, the remaining steps are done automatically . How do pilots start a plane? It’s not as simple as turning a key or pushing a single button. Starting a plane is ‘a little more complicated’ than starting a car, said Captain Piers Applegarth, a representative of the British Airline Pilots Association (BALPA). The retired training captain said an air start motor rotates the jet engines before adding fuel and starting the ignition. He said: ‘This means that there are a few levers and buttons that need to be moved. On modern aircraft, most of this is done automatically once the start sequence is initiated but a pilot can still start it manually.’ Flight attendants eat the same meals that are provided to passengers if the airline bothers to feed them at all . Is the crew served the same food as passengers? If meals are provided by the airline, pilots do not eat the same reheated chicken or pasta dishes that are served to passengers in economy. To reduce the risk of food poisoning, the captain and co-pilot usually eat different meals, said Mr Applegarth. Like passengers, the flight crew can bring their own food on board, but the meals provided to them are the same or variations of the meals provided to passengers in business class. Caterers will sometimes load meals designated specifically for the crew, said Patrick Smith, a pilot and author of Cockpit Confidential. He said: ‘At my airline we are given a menu prior to departure and will write down our entree preferences – first choice, plus at least one alternate. ‘Eating in the cockpit can be messy, so on international flights I usually take my meals in the cabin, on my rest break. ‘With potential illness in mind, pilots are encouraged to eat different entrees, but this is not a hard and fast rule. In practice it comes to down to your preferences and what’s available.’ Flight attendant Sarah Steegar, who works for a major US airline, said if – ‘and that’s a big if’ – an airline provides food to cabin crew it will be the same food that is served to passengers. But it’s rare for some airlines to provide meals to flight attendants on flights under 12 hours, she added. ‘If there are meals left over we can have that. Many of us try to bring our own food, but it’s a challenge, considering periods of time with no refrigerators and different liquid restrictions and customs laws. ‘Fun fact: the UK is the most difficult when it comes to trying to bring food for ourselves.’ The Airbus A350 has private sleeping quarters for flight attendants on long-haul flights . Where do pilots and cabin crew sleep and go to the loo? Planes that fly long-haul routes which require more than two pilots usually contain private bunks for the flight crew, said Mr Applegarth. In other cases pilots try to catch some shut-eye in special rest seats allocated for them within or near the cockpit, or within the passenger cabin, he added. Mr Applegarth said: ‘Generally flights less than about 10 hours and 30 minutes only carry two pilots. For longer flights extra pilots are carried so that each pilot can have a chance to sleep and be rested for the landing.’ The Airbus A380, which is the world’s largest passenger airliner, has private sleeping quarters below its decks which flight attendants use for rest. Mr Smith said: ‘Flight attendants also work in shifts, and similarly to the pilots their rest quarters can either be a designated block of cabin seats or a separate room somewhere. ‘Many flight attendant rest quarters are located in the far aft of the plane, above or below the main deck, and can accommodate six or more cabin crew simultaneously.’ When nature calls, flight and cabin crew on most planes use the same toilets as passengers. The Boeing 747, the original jumbo jet, has a lavatory just for pilots. Prior to any flight the crew will verify that the toilets have been serviced and the waste tanks are empty . What happens if a toilet’s tank fills up? The toilets cannot be emptied in the sky, so that means all of the human waste is stored on board until the plane lands and a ground crew empties the tanks. ‘If the toilet becomes full then it is out of action and the flight attendants block out the toilet so it can't be used,’ said Mr Applegarth. Prior to any long-haul flight the crew will verify that the toilets have been serviced and the waste tanks are empty, Mr Smith added. He said: ‘It seldom happens, but if a particular lavatory tank fills or overflows en route, that lav will be closed off. It's extremely unusual for all of the lavs to become unusable – a serious situation that could result in the flight being diverted.’ Pilots monitor multiple frequencies and occasionally chat with other pilots about turbulence . Do commercial pilots communicate with other pilots during a flight? Mr Applegarth said pilots are always monitoring multiple frequencies and occasionally chat with other pilots who are in the air. He said: ‘We are always listening out on one frequency that air traffic are using and we use another radio tuned to a special frequency to listen out for aircraft which may have an emergency. ‘We also have a chat frequency that we can use to share information such as turbulence.’ The amount of fuel that is consumed depends on the aircraft type, altitude, flight path and weather . How much jet fuel is required? A jet engine typically burns about 2,400 pounds (approximately 1,100 litres) of fuel per hour, with planes carrying a lot more fuel than required for the individual trip. Mr Applegarth said: ‘For a flight we load an amount of fuel that is the sum of the fuel needed to fly the route, an extra amount added for contingency – for instance, in case we have to hold – some extra fuel so that we could divert to another airfield and we also have to land with a minimum amount of fuel even if we used all the fuel just mentioned. ‘So after a flight we always have a minimum of fuel on board. On top of this, pilots can also decide to add extra fuel for each trip if they think it will be needed above and beyond that above.’ Mr Smith said the amount of fuel that is consumed depends on the aircraft type, altitude, flight path and weather. A Boeing 767 on a flight from London to New York would burn about 75,000 pounds of jet fuel (34,020 litres), while a Boeing 747 or an Airbus A380 might use twice that amount, he said. Condensation trails are similar to the fog that results when a person exhales on a cold day . Why do planes leave long white trails in the sky? These condensation trails form when humid exhaust from jet engines cools very quickly in colder and dryer air at higher altitudes. Mr Smith said: ‘It's not unlike the fog that results when you exhale on a cold day. In other words, contrails are clouds. ‘Water vapour, strange as it might seem, is a by-product of the combustion within jet engines, which is where the humidity comes from.’ 'Not even the world's strongest man would be able to open' a plane door in mid-air, said one expert . What would happen if a plane’s door suddenly opened mid-flight? This ranks among passengers’ biggest fears, but Mr Applegarth said it is extremely unlikely, if not impossible, for someone to open the door as the pressure inside the plane is much greater than the pressure outside. He said: ‘This means the door is being forced closed. Not even the world's strongest man would be able to open it.’ Mr Smith added: ‘In addition to any mechanical latching, most aircraft doors open inward before they open outward, and like a drain plug they are held in place by the forces of the pressurised cabin. ‘If a door were to open somehow the result would be a very quick decompression, though in all likelihood not a destructive or catastrophic one.’ Margins on the average economy class ticket are similarly thin, said pilot and author Patrick Smith . How much money does an airline pocket from each ticket sale? A recent Travelzoo study found that British Airways’ profit margin for each £690 ticket it sold for a flight from London to New York was just £4.24, accounting for 0.61 per cent of the overall cost. Almost the entire cost of the return flight went towards taxes, surcharges and operating costs. Mr Smith said budget airlines probably make nothing from their super-cheap promotional fares, and margins on the average economy class ticket are similarly thin. ‘Margins on a premium-class long-haul fare costing thousands of pounds, on the other hand, will be much higher,’ he said.
Flying is a thrilling experience but is full of mystery for most passengers . MailOnline Travel spoke to experts to answer common questions . To reduce the risk of food poisoning, pilots do not eat the same meals . Larger planes have private sleeping quarters for flight attendants . 'The world's strongest man' wouldn't be able to open a door mid-flight .