Departures: work backwards from special assistance, not from boarding
If you've booked assistance with your airline, that meeting point has its own timing, usually earlier than standard check-in. Handing over a powered wheelchair adds more: batteries need to be identified and sometimes disconnected, the chair has to be tagged, and someone has to arrange the aisle chair or the walk to the gate.
We plan the pick-up backwards from your assistance time rather than your departure time, and we build in slack. As a working rule we aim to have you at the terminal three hours ahead for international and two hours for domestic, but tell us your own preference and we'll work to it. Some passengers want more, and nobody has ever complained about arriving unhurried.
