To begin a journey. “We set off really early this morning, that’s why I’m so tired.
To go away on holiday, to escape for a while “I’m really stressed at work and what I really need is to get away.
When the plane leaves the ground. “The plane took off on time.”
To pick somebody up is to go somewhere to collect someone, usually by car. “I’ll pick you up at the station at 6 in the morning.
To take someone somewhere by car. “I’ll drop you off at the airport this afternoon.”
You arrive and register at a hotel or an airport. “When we check in at the airport they’ll give us our boarding card”
You pay the bill at the end of your stay at a hotel.
When you go to the airport, port, train station etc to say goodbye to someone. We’ll see you off at the airport.
Explore what is around you. “After we checked in to our hotel we wanted to look around the local area to see what it was like.”
When you enter a plane, bus, train, horse, bike.
You leave a plan, bus, train, bike.
When you enter a taxi, car.
The moment the plane touches the ground and lands. “Our plane touched down at half past seven in the morning.”