American Airlines: Round Trip Flights from Detroit, Michigan (DTW) to San Diego, California (SAN) (vice versa) from $144

Travel availability (subject to change):

Departs Detroit, Michigan (DTW): Mar 15, 22; Apr 18, 25, 26; May 2, 3, 9, 10, 16, 31;
Returns Detroit, Michigan (DTW): Mar 21, 28, 29; Apr 4, 5, 11, 12, 18, 19, 24, 25, 28; May 1, 2, 3, 5, 7, 8, 9, 12, 15, 16, 22, 23, 30
Departs San Diego, California (SAN): Mar 15, 29; Apr 5, 19;
Returns San Diego, California (SAN): Mar 21, 22, 28; Apr 4, 11, 18, 25, 26; May 2, 3, 9 10, 16, 17, 23

Example flight

Depart San Diego, California (SAN) March 15, 2017
Return San Diego, California (SAN) March 21, 2017