noun
Specifically the deck where people watch planes and see off or welcome travelers; common at Japanese airports.
空港の送迎デッキから飛行機の離陸を見た。
I watched the plane take off from the airport observation deck.
展望デッキ is a general observation deck (e.g., at a tower or building), while 送迎デッキ is specifically at an airport for seeing off or welcoming travelers.
Compound of 送迎 (seeing off and welcoming) and デッキ (deck), a straightforward modern term.