Mesa Airlines Inc. is expanding its partnership with United Airlines with the addition of 12 new Embraer 175 aircraft.

The delivery of the 12 additional aircraft is scheduled to begin in May 2017 and will create more than 500 new jobs, according to Mesa Airlines.

These aircraft will bring Mesa’s E175 fleet count to 60 and the Company’s total number of large regional jets to 145. Mesa’s United Express fleet will now total 80 aircraft, including 20 CRJ700s.

“We are delighted, once again, to extend and expand our partnership with United Airlines with the addition of 12 new Embraer 175 aircraft,” said Chairman and CEO Jonathan Ornstein. “We appreciate United’s confidence and will continue our focus on providing the highest levels of customer service and reliability in the industry.”

Since United’s E175 program launched in June 2014, Mesa added 48 E-Jets to its United Express hub in Houston, with every aircraft in service on time or ahead of schedule.

“We have grown our E-Jet fleet from 0 to 60 in record time and understand the importance of both top-notch performance and low cost operations,” said Mesa’s Chief Operating Officer John Selvaggio. “Combining the two, Mesa has become the fastest growing U.S. air carrier and the airline of choice for growth in the regional industry.

Mesa has created more than 2,000 jobs over the past three years, and believes there are significant opportunities to continue this growth and provide thousands of additional careers for some of our country’s most promising pilots, flight attendants and mechanics.