I remember BI, Braniff International, with their 10 different colors of fuselage in the 70s. My favorite is the orange-colored 747, the Great Pumpkin.

There was also PSA, Pacific Southwest, on the west coast. All their planes showed a "big grin".

Hughes AirWest always reminded me of a banana with the whole fuselage painted in bright yellow.

The one I miss the most was a classic airline in the Far East, Civil Air Transport (CAT), in the 50 - 60s. A dragon was painted near the nose of their aircraft. The bulkhead that divided the first and economy classes in the CV-880 jet had an arched opening, like a Chinese doorway.