飛行機 and 空港: aircraft and airport roles
Distinguish the vehicle boarded from the departure or arrival facility.
The aircraft boarded
飛行機 (ひこうき) means aircraft or airplane. 「飛行機に乗りました」 means boarding a plane.
「飛行機が離陸しました」 says the plane took off. Boarding and takeoff are different stages.
The airport used
空港 (くうこう) means airport. 「空港で友人を待っています」 means waiting for a friend at the airport.
「空港まで迎えに行きました」 says the speaker went to the airport to meet someone. It does not establish that the speaker flew.
Arrival targets and sequence
「空港に着きましたが、まだ飛行機には乗っていません」 says the speaker reached the airport but has not boarded the plane yet.
「飛行機を降りて、空港の出口へ向かいました」 places heading toward the airport exit after leaving the aircraft. 向かう does not establish arrival at the exit.
Does reaching the airport mean the person has already boarded?
Show the answer and why
No. Arrival at the facility and boarding the aircraft are separate stages.