Spirit Airlines Inc. pilots went on a strike early morning on Sunday. The pilots have been trying to reach on an agreement with the union for more than three years now. They started with the discussions again in this week. The Company negotiated with pilots till 5 in the morning to reach to some agreement, but the latter were not satisfied and walked off.

According to Spirit Airlines President and CEO Ben Baidanza, pilots have refused an increment of more than 30% at a cost of $70 million in the last five years. The latest event has not only spelt fresh trouble for customers, but has also put the bread and butter of about 2,000 workers of Spirit airlines at risk .

The airline had to cancel its flight yesterday. Spirit is a regular scheduled U.S. passenger airline since 2005.

Spirit pilots have said that also want their pay to be on the same level as the pilots of Jetblue Airways and Southwest Airlines Co. get.

The airline controls about 150 flights in a day with 16,000 passengers in them. Most of the flights have their destination in eastern the U.S., Mexico, Caribbean and Latin America.

The airline is refunding the fares of the passengers.

Misty Pinson, the airline spokeswoman, has not commented on the strike yet.