The union launched at the beginning of the month a series of nine strike days at the Barcelona, Málaga and Majorca airports to obtain raises and better working conditions.
The strikes forced the low-cost British airline to cancel and delay flights at the beginning of the peak European summer vacation season.
USO said that a staff assembly had approved the deal, which will see flight crews get a 22 percent pay hike spread over three years, as well as special compensation for working on scheduled days off.
Remaining strike days planned for July 29th, 30th and 31st have been cancelled.
Irish budget airline Ryanair has also been hit by strikes in Spain.
Strikes by airline and airport staff across Europe have led to misery for travellers as the aviation industry was hoping a bumper summer season would help make up two dismal years due to the Covid-19 pandemic.
The industry had slashed jobs due to the pandemic and had difficulty rehiring staff to handle the boom in travellers, while staff complain that wages and working conditions need to improve.