Mazowiecki Air Base isn't the largest air force base in Poland, but it's considered the most important one for no other reason than its responsibility to protect Warsaw.
Ever since Poland joined NATO, all Polish military airports have been open to NATO forces. However, Mazowiecki Air Base has seen the most landings of NATO military aircraft and the transportation of military supplies because it is less than 100 kilometers from Warsaw, making it the most convenient airport for landings.
Today, a C-5 Galaxy transport aircraft is to make an emergency landing at Mazowiecki Air Base.
There was no prior notice, no official endorsement, it wasn't part of the NATO system, nor was it invited for any official business. It was just a sudden notification to Poland for an emergency landing.
Although such an occurrence is highly irregular, since it is the United States, no, since it is a request from a U.S. ally, of course, it must be accommodated.
