BARCELONA, Spain (AP) — Hundreds of passengers have been stranded at Barcelona's airport because of major delays and cancelations involving Spanish airline Vueling.

Problems started Friday, coinciding with the start of summer vacation for many passengers departing or going through Barcelona's airport.

Delays of up to 20 hours provoked a domino-effect that kept rippling through Sunday at El Prat airport, with scenes of stranded travelers seeking answers.

The local government summoned Vueling for an explanatory hearing on Monday, with the threat of possible sanctions.

The company, founded in 2004, acknowledged problems with operations, saying they will try to reinforce shifts. The airline confirmed 14 cancellations on Sunday.