The next time you fly in a commercial jet, look out the window during takeoff and you’ll probably see that a section of the wings extends by a few feet. Although there are exceptions, most commercial jets feature extended wing flaps such as this. The wing flaps extend during takeoff and retract once the plane has reached cruising altitude. Because the wing flaps retract back to their normal position, though, many passengers wonder what purpose (if any) they serve. In this post, we’re going to reveal the purpose of extended wing flaps and why they are so common with commercial jets.

How Extended Wing Flaps Work

In a typical commercial jet, the wing flaps — the section at the very back of the wings — extends by a few feet during takeoffs and landings. Additionally, the wing flaps can be angled, which is a common practice among commercial airline pilots during takeoffs and landings.

The purpose of extended wing flaps is to create additional lift so that the plane can take off with greater ease. As previously mentioned, wing flaps can be adjusted to a particular angle. While in the cockpit, the pilot can adjust the angle of the plane’s extended wing flaps to create additional lift. A 30-degree angle, for example, allows the plane to take advantage of the wind so that it’s lifted into the air.

Normally, extended wing flaps are retracted back to their original position once the jet has reacted cruising altitude. This is done to reduce drag against the jet. With the wing flaps extended, there’s greater drag, thereby slowing the jet down. Even if the loss of speed isn’t enough to make a jet fall out of the sky, it will still force it to consume more fuel. Therefore, most pilots retract the wing flaps after takeoff, allowing for a faster, more efficient flight.

Extended wing flaps are also used during landings. Pilots must slow down the jet prior to landing. Otherwise, they may struggle to come to a complete stop within the runway. Extended wing flaps allow pilots to slow down their jet before landing by adjusting them to the appropriate angle.

The Bottom Line on Extended Wing Flaps

Extended wing flaps are a feature found on most commercial jets that allows for easier takeoffs and landings. They work by using a specific angle to push the plane upwards. Once the jet has reached cruising altitude, the pilot will typically retract the wing flaps back to their original position.