Travelers with ambitious travel plans may find new multicity routes at bargain rates that may make a layover worthwhile. International airlines are adding free stopovers and other incentives to many popular routes, all to make midway hubs a worthwhile second destination.

Qatar Airways recently began a promotion for summer 2018, offering a free overnight stay and complimentary transit visas in Doha, the capital of Qatar, from May 7 to Sept. 30. Travelers booking a flight through Doha can stay for up to 96 hours on the same ticket. On the first night, passengers can choose complimentary accommodations from a list of luxury hotels including the Four Seasons Hotel Doha or the Marriott Marquis City Center Doha Hotel, with a second night at $50 (beyond that travelers must pick up their own hotel expenses).

The Iceland-based, low-cost carrier WOW air started its free stopover service in Reykjavik for travelers flying from the United States to Europe last year. This summer, WOW will introduce flights from Chicago and Pittsburgh with stopover options in the Icelandic capital on tickets to European destinations including Barcelona, Paris and Stockholm. There is no limit on the length of a stopover.

Last summer, TAP Portugal introduced its one-to-three-night stopover program in Lisbon or Porto on flights to destinations in Africa and Europe, including the Azores. Passengers may take advantage of discounted offers from hotels, restaurants and attractions found in the airline’s Stopover App.

Finnair also offers free stopovers in Helsinki for up to five days on flights between North America and Europe or Asia.

Several other airlines offer stopover programs for longer layovers as well. Icelandair, for example, allows stopovers of up to five days in Reykjavik. Emirates stopovers in Dubai include free shuttle transportation between the airport and hotels, buffet breakfasts and 24-hour check-in.

“It used to be that stopovers were expensive because you had to pay for the privilege,” said George Hobica, founder and president of Airfarewatchdog. They are common on airlines owned or partially owned by the governments of the countries they serve, he said, in an effort to boost tourism and business at the airport.

“Now you can see two cities often for less than the price of one,” he said.

© 2018 The New York Times Company