SEATAC, Washington — Background music is no longer an afterthought at many airports, which are hiring local musicians and carefully curating playlists to help lighten travelers’ moods.

London’s Heathrow Airport built a stage to showcase emerging British performers for the first time this summer. The program was so successful the airport hopes to bring it back in 2025. Nashville International Airport in Tennessee has five stages that host more than 800 performances per year, from country musicians to jazz combos. In the Dominican Republic, Punta Cana International Airport greets passengers with live merengue music.

Chicago’s O’Hare and Midway airports have more than 100 live performances each year. Phoenix’s Sky Harbor International Airport began a live music program five years ago and now has two stages featuring local artists.

Tiffany Idiart and her two nieces were delighted to hear musicians during a recent layover at Seattle-Tacoma International Airport.

“I like it. There’s a lot of people here and they can all hear it,” said Grace Idiart, 9. “If their flight got delayed or something like that, they could have had a hard day. And so the music could have made them feel better.”

Airports are also curating their recorded playlists. Detroit Metro Airport plays Motown hits in a tunnel connecting its terminals. Austin-Bergstrom International Airport in Texas has a playlist of local artists compiled by an area radio station. Singapore’s Changi Airport commissioned a special piano accompaniment for its giant digital waterfall.

Music isn’t a new phenomenon in airport terminals. Brian Eno’s “Music for Airports,” an album released in 1978, helped define the ambient music genre. It’s minimalist and designed to calm.

But Barry McPhillips, head of international creative for Mood Media, which provides music for airports and other public spaces, said technology is enabling background music to be less generic and more tailored to specific places or times of day.

Mood Media, formerly known as Muzak, develops playlists to appeal to business travelers or families depending on who’s in the airport at any given time. It might program calmer music in the security line but something more energizing in the duty-free store.

“We see it as a soundscape,” McPhillips said. “We design for all of these moments.”

There’s a science to Mood Music’s decisions on volume, tempo, even whether to play a song in a major key versus a minor one, he added.

“How do we want to affect their mood at that moment?” McPhillips said. “It’s not just like, ‘Here’s a load of songs.’ It’s a load of songs for that 10-minute segment, and then we move to the next 10 minutes.”

The programs also benefit musicians, who get paid to perform and gain wider exposure.

Otto Stuparitz, a musicologist and lecturer at the University of Amsterdam who has studied airport music, said airports should think about their selections. Music that’s meant to be actively listened to can be distracting in an already chaotic environment, he said.