What would happen if an aircraft takes off with too much flap extended?

It will take much longer for the aircraft to take off think of flaps as a parachute, when you're landing the flaps slows you down but you will still move forward and while you're taking off if you put the appropriate flap the air will be pushed down due to the shape of the flap therefore creating lift

The flap increases lift. If you have "too much" out the plane will lift off earlier than usual and at a lower speed. There are two vital things in flying, altitude and air speed. When you take off you have zip for altitude so you need speed. Taking off at a speed that is slower than the recommended airspeed is not a good idea.

Flaps are “increased lift devices”. In a small aircraft, the plane will take off early and want to climb faster than normal. However, it will have increased drag and not enough power to sustain the high pitch attitude. The wing will stall if the pilot is not watching the airspeed, which would be rapidly decreasing, and correct the situation. He must take action to pitch down to get the airspeed up, and use significant pressure on the yoke to do so. Most pilots are trained to handle this situation and take the correct action. A newer pilot may not understand what is happing quick enough to take action, and stall the plane. Stalling an aircraft This close to the ground is incredibly dangerous and will most likely result in crash.

I did that once with a 152: Just poor rate of climb.

Depends on the aircraft.

Some aircraft like the Lake Buccaneer only have one flap setting, and takeoff and landing are done with them fully extended.

An aircraft with split flaps like a DC-3 or Cessna 310 won’t leave the ground as the flaps produce an excessive amount of drag.

And a Cessna 150 or 172 certainly will climb with full flap though not very well or at high density altitudes. I’ve seen several take off with full flap accidentally as well as a straight Navajo.

Also, a go around is not equivalent to a full flap takeoff. With a go around you have the advantage of the extra airspeed which is approach rather than rotation speed and flaps are retracted before climbing.

In modern aircraft the systems would inform the pilot. The same if the flaps had not been set.

Depends on how much more flap is extended. If it's far too much, the aircraft may never get off due to the increased drag.

Pass away

Take off distance would increase.

The performance is already known and documented, as this is the condition of a go-around, an aircraft having to get back in the air because of something on the runway.

Heavy Drag unnessary difficulty in taking off.