Definition
The minimum airspeed, in knots or miles per hour, at which an aircraft generates enough lift to leave the runway and begin climbing. Takeoff velocity is determined by the aircraft's weight, configuration, and the air density at the time of takeoff, and is published in the aircraft flight manual as a target speed for rotation and liftoff.
Plain English
The speed the airplane has to be moving down the runway before the wings can lift it into the air.
Context Anchor
Used in takeoff performance discussions when explaining how weight, air density, wind, runway surface, and runway slope affect the distance needed for takeoff.
Derivation
From 'takeoff' (the act of leaving the ground) and 'velocity' (Latin velocitas, meaning speed). In flying, velocity refers specifically to airspeed — the speed of the airplane through the air, not its speed across the ground.
Why Pilots Care
Determines the minimum runway length required and directly affects whether the aircraft can safely lift off before running out of pavement.
Grounding Statement
On takeoff, the airplane is not ready to fly just because it is moving; it must reach enough speed through the air for the wings to hold it up.
Intuition Check
Do not read takeoff velocity as simply speed over the ground. For lift, what matters is speed through the air; wind can change how much runway is needed to reach that speed.
Example Sentence 1
On a hot day at a high-elevation airport, the required takeoff velocity stays the same, but it takes a longer ground roll to reach it.
Example Sentence 2
Higher density altitude increases the takeoff velocity needed to become airborne.