The Three Most Useless Things in Aviation
- Feb 1
- 5 min read
Spend enough time around any airfield, and you’re bound to hear a few old adages passed down from seasoned instructors to their students. This hangar talk, polished over decades, often contains nuggets of pure aviation wisdom. Sometimes, however, it comes in the form of a slightly sarcastic, tongue-in-cheek list. One of the most famous is the answer to the question: “What are the three most useless things to a pilot?”
The classic, world-weary answer is:
The runway behind you.
The sky above you.
The air in your fuel tanks.
At first glance, it’s a cynical but amusing take on the realities of flight. Once you’re committed and airborne, these three things seem utterly irrelevant to your immediate situation. But dismissing them as merely a joke would be a mistake. These aren’t hard rules; they are powerful mental cues. Their real value isn’t in their literal meaning, but in forcing a pilot to consider the critical moments when they stop being useless and become the most important considerations in the sky. Let’s break down why these old sayings are much smarter than they sound.
The Runway Behind You
Once your wheels leave the tarmac and you are climbing away, the strip of runway disappearing behind you is genuinely useless. You cannot go back and reclaim it, and you cannot rely on it if something goes wrong after take-off. From that moment on, whatever runway you did not use is gone forever. In that sense, the saying is absolutely true.
When it stops being useless: During the take-off roll.
The runway only has value while you are still on the ground deciding how and where to start your take-off. Beginning a departure partway down the runway means voluntarily giving up performance margin that you may desperately wish you still had a few seconds later. If an engine problem occurs shortly after lift-off, the length of runway you left unused is exactly the length you cannot get back.
This is why good airmanship means using the full length of runway unless there is a clear and justified reason not to. On short runways, grass strips, or when conditions are less than ideal, such as wet surfaces or high density altitude, every metre of available runway is safety margin. The lesson behind the saying is simple: once the runway is behind you, it is useless, so make sure you have used as much of it as you reasonably can before you ever open the throttle.
The Sky Above You
This one seems the most obviously useless. You’re a pilot. The sky is your entire domain. What good is the bit of it that’s directly above your head? It’s just more empty space, isn’t it? This line is often delivered with a shrug, implying that it’s the ground below you that warrants all your attention.
When it stops being useless: For terrain, engine failure, weather, and airspace.
The sky above you is not empty at all. It is a safety buffer. Height gives you time, and time gives you options. In the event of an engine failure, altitude is what allows you to glide, assess the situation, choose a suitable landing area, and configure the aircraft in a controlled way. More height does not guarantee a good outcome, but less height almost always reduces your choices.
That vertical space is also your clearance from terrain and obstacles. When flying at low level or in hilly areas, the sky above represents your margin for error. Losing it means committing to narrower, more demanding decisions with less room to recover.
For pilots flying under Visual Flight Rules, the sky above also governs weather safety and legality. The cloud base is a hard ceiling you cannot cross without losing visual reference. Even when the rules only require you to be clear of cloud, flying immediately beneath it is rarely wise. Other aircraft may be descending through the cloud leaving little time to react.
Finally, the sky is divided into layers of controlled airspace. The air above you may be the base of a terminal control area or a higher class of airspace that you are not cleared to enter. Climbing without awareness can quickly turn an otherwise routine flight into an infringement.
Far from being useless, the sky above you is a critical reserve of safety, legality, and decision-making space. Knowing how much of it you have, and choosing to keep it, is a fundamental part of good airmanship.
The Air in Your Fuel Tanks
This saying is often phrased in different ways, such as “the fuel still in the bowser” or “the gallon you wish you had.” The meaning is the same: fuel that is not on board your aircraft is useless once you are airborne. When the propellor is turning, the only fuel that matters is what is already in your tanks. No amount of fuel left in an underground tank at the airfield will help you if the engine coughs a hundred miles from home.
When it stops being useless: During pre-flight planning.
This is perhaps the most important lesson of the three. While the fuel in the bowser is useless in the air, the thought process about how much fuel to carry on the ground directly affects the safety of the entire flight. Fuel planning is not just about reaching your destination. It means accounting for taxi, take-off and climb, wind, delays, and then adding a proper reserve for holding or diverting, all while remaining within runway performance, weight, and balance limits.
Within those limits, carrying extra fuel increases your margin of safety. It gives you time to deal with unexpected headwinds, weather deterioration, airspace delays, or a missed approach. Running out of fuel has immediate and severe consequences. Carrying a little more than planned does not.
The saying exists to push that decision-making onto the ground. Once airborne, your fuel gauge is a clock that only counts down. The moment you wish you had taken more fuel, it is already too late. Good airmanship means making conservative fuel choices before the engine starts, because fuel you did not load is the one resource you can never recover in flight.
Why These Sayings Still Matter
These three "useless" things are not useless at all. They are clever, reverse-psychology reminders of where a pilot's focus should be at critical stages of flight. They teach us that the most important decisions are often made before the flight even begins.
The runway behind you is useless once airborne, so use every available metre wisely before you open the throttle.
The sky above you is useless as a destination, so use it to ensure safe clearance from terrain, weather, and airspace.
The fuel in the bowser is useless in the air, so make conservative fuel decisions on the ground while you still can.
The real power of these sayings comes from knowing precisely when they stop applying. They are not absolute truths but mental triggers, designed to embed the core principles of airmanship deep into a pilot’s mindset. Understanding this distinction is a key step in your journey from student to a confident, safe, and well-prepared pilot.
If you want to turn these old aviation sayings into practical judgement rather than catchy lines, that is exactly where QuizAero Bitesize fits in. Each short module is designed to reinforce the decisions that actually matter in flight, from take-off performance and airspace awareness to fuel planning and threat management. Instead of memorising slogans, you build the understanding behind them, in focused lessons that are easy to revisit whenever you need a refresher. It is a simple way to sharpen your thinking, strengthen your airmanship, and carry the right priorities with you every time you fly.