Atlanta ? Airlines have offered more legroom, televisions and even martinis on flights to draw customers in a highly competitive market. In the latest unusual effort, Delta’s low-fare carrier, Song, will give free tickets to passengers who are nice to one another.

Help another passenger carry a bag, stay upbeat during a difficult situation or assist a flight attendant and you could earn one of 5,000 roundtrip tickets Song will give away in June.

Song hopes the program will build customer loyalty and generate more revenue for Delta Air Lines, which has lost more than $3 billion in three years and recently warned about the possibility of bankruptcy.

In the promotion, each flight attendant will get four tickets to give away to passengers at his or her discretion. The tickets will be good for travel between Sept. 7 and Nov. 10 in any of the 12 cities Song flies.

As he got off a Song flight Wednesday in Fort Lauderdale, Fla., John Murphy, a 34-year-old financial consultant from New York, said he was intrigued by the promotion. “Perhaps it will put people in a better mood on airplanes,” he said.