When Elvis and Marie go to escape the crowd, Marie asks Elvis, "Can you row a boat?" Elvis replies "Can I row? Didn't you ever see 'King Creole?'" - Elvis did have a scene on a boat in "King Creole," but it was a steamboat... no rowing required.
The jet in the movie ending is a Cessna Citation 500. Although commercially available since 1971, the airplane on the movie (registry N888GA - cn 500-0132) was built in 1973, one year after the movie events.