When you take a photo of an airliner, it is generally regarded as "public domain" subject matter.
However, when you sell a photo of an airline's aircraft, you are "profiting from proprietary subject matter". (I realize that you aren't offering this photo for sale, but many other shots on this website are available for purchase - with no percentage going to the subject airline).
It is creepy that a large airline would resort to stealing photos from this website.
But it is also possible for any airline whose aircraft photos are SOLD on this website to retroactively require you to obtain licensing to use their proprietary images and likenesses.
Military Aircraft Every type from fighters to helicopters from air forces around the globe
Classic Airliners Props and jets from the good old days
Flight Decks Views from inside the cockpit
Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior
Cargo Aircraft Pictures of great freighter aircraft
Government Aircraft Aircraft flying government officials
Helicopters Our large helicopter section. Both military and civil versions
Blimps / Airships Everything from the Goodyear blimp to the Zeppelin
Night Photos Beautiful shots taken while the sun is below the horizon
Accidents Accident, incident and crash related photos
Air to Air Photos taken by airborne photographers of airborne aircraft
Special Paint Schemes Aircraft painted in beautiful and original liveries
Airport Overviews Airport overviews from the air or ground
Tails and Winglets Tail and Winglet closeups with beautiful airline logos