Most had an American theme name. If you weren't American, some of them probably seemed quaint/odd/weird.
This is not quite accurate. Actually, most of the aircraft (at least in the 80s) had generic names. In fact, some even had German names, for the IGS (intra-Germany routes to Berlin, et al) services. Some did have patriotic American names, or the names of American cities, but these were by no means the majority of the fleet: Some random examples:
727s: Matchless, Rainbow, Skylark, Dauntless, Eclipse, Empire, Westwind, Whirlwind, Zephyr, Yankee, Archer, Guiding Star, Defiance (PA 759, crashed in Metairie, LA).
737s: Tempelhof, Spandau, Hornet, Charlottenburg, Dawn, Georgia, San Diego, Schoneberg, Berlin.
747s: Witch of the Wave, China Clipper II, Maid of the Seas (PA 103, crashed in Lockerbie), Constitution, Moscow Express, Flying Cloud, Ocean Express, Ocean Pearl, Juan T. Trippe.
A300s: America, Chicago, Dallas, Miami, Tampa, Costa Rica, Guatemala, Washington, Panama.
A310s: Frankfurt, Munich, Miles Standish, Golden Light, Golden Rule, Golden State, Golden West, Midnight Sun, Mayflower, Betsy Ross, Victory, Queen of the Skies.
DC-10s: Morning Star, Eclipse, Aurora, Star of the Union, Star King, Star Light, Star Gazer, Atmosphere, Glory of the Skies.
L-1011s: Bald Eagle, War Hawk, Wild Duck, White Falcon, Flying Eagle, National Eagle.
A complete list of the Clipper names is available at .