United Airlines marks the 40th anniversary of the MileagePlus program this May and is giving away four million miles to four lucky healthcare workers in its new Essential Healthcare Worker Contest.

From now until May 17, 2021, you can nominate any frontline healthcare worker in the U.S. that embodies some of United’s core values, like making the world a safer place, showing compassion and kindness to their neighbors, being dependable and determined.

Submissions will be reviewed by Dr. Pat Baylis, the corporate medical director at United, as well as Luc Bondar and Dr. Jim Merlino, the chief clinical transformation officer at Cleveland Clinic. The four winners are to be announced in June and will receive one million MileagePlus miles.

"Throughout the past forty years, MileagePlus has evolved to meet the ever-changing needs of our members as well as reward their loyalty," said Luc Bondar, vice president of marketing & loyalty and president of MileagePlus at United. "That's why we celebrate this major milestone by offering our members generous promotions throughout May. We're also taking this occasion to launch the contest to show appreciation for the healthcare workers who stepped up to protect our communities during the pandemic."

MileagePlus members also receive some extra bonus promotions throughout the month of May. Members can earn up to two times the miles on eGift cards using the United MileagePlusX app; earn up to 7 miles per each dollar spent when they book cruises through 2023 with United Cruises; earn 40 percent off when they purchase miles through May 10; and can enter a chance to win bonus miles in the 1,000,000 Miles Sweepstakes, which begins May 10 and ends June 10.

Please click here to nominate a healthcare worker. To see a full list of MileagePlus promotions, please click here .