At Airports, there are sometimes Jetways that have Airline logos on them. Does this mean they lease those gates from the airport? At Manchester, Delta has their Gates at 5 and 6, American at 8 and 9, and Southwest from 11-15(A). United doesn’t really have a logo at any of their gates at MHT, they only use Gate 1.
US is different than Europe, as most jetways in Europe are mostly made from glass, and is served by multiple airlines, while in the US whole concourses are served by only one airline.
Manchester don’t have a big airport as far I’m concerned, so instead of having whole concourses, they have separate gates