The C-101 -- the same aircraft used by Spain's air force Eagle Patrol aerobatics team -- was on a "training flight" when it crashed near the resort of La Manga, a statement said.

On board was a flight instructor who "was able to eject before the plane crashed in the sea".

A video filmed by a witness and posted on Twitter shows a small aircraft falling at a near vertical before trying to straighten up and hurtling into the water.

Emergency services said a search and rescue mission has been set up which includes the air force, navy, firefighters and coastguards.

On Twitter they said the pilot "had not yet been located".

The plane came down near an air base outside the town of San Javier.