'Aircraft' is good. 'Aeroplane' is also fine. 'The jet', if you're flying it.
Take off is by far the most dangerous time on an airliner. Just after rotate, at a speed so low you're
entirely dependent on the complex system of slats and flaps keeping the aircraft airborne as it accelerates - meanwhile, the engines are working flat out and if something's going to go wrong with one of them, this is the time. And if it does, you'd better pray that the PF has the reflexes to immediately get the correct rudder applied and the room to lower the nose to maintain VMcA, or you're fúcked.