United Airlines

United Airlines is based in the USA and is one of the world’s largest airlines with global flying routes, and offers additional routes via their partnership in the Star Alliance. As of August 2015 they only offer vegan meals on their international flights, and the quality of the meal you receive varies based on the quality of the caterer they are using in that departing airport.

Star Alliance members include (as of August 2015):
Air India
Air New Zealand
ANA
Asiana Airlines
Austrian
Avianca
Avianca in Brazil
Brussels Airlines
Copa Airlines
Croatia Airlines
EGYPTAIR
Ethiopian Airlines
EVA Air
LOT Polish Airlines
Lufthansa
Scandinavian Airlines
Shenzhen Airlines
Singapore Airlines
South African Airways
SWISS
TAP Portugal
THAI
Turkish Airlines
United Airlines