Flights to Iran were a temporary casualty of Priceline’s $1.8 billion acquisition of Kayak, but Iran itineraries on Kayak returned today after a hiatus.

If you did a search for a New York-Tehran flight on Kayak yesterday, you’ll probably see a message: “An error occurred while trying to perform your search, please try again.”

Priceline spokesperson Leslie Cafferty says Kayak’s Iran search results were temporarily discontinued after the acquisition to ensure Kayak was in compliance with U.S. Office of Foreign Assets Control’s prohibitions against doing business with certain airlines or tour operators in Iran.

Cafferty says Kayak’s flight-search options for Iran are slated to resume as soon as Thursday and will include airlines such as Egyptair, which fly to Iran and are not a target of U.S. sanctions. They also include search results for airlines such as Aeroflot, Turkish Airlines, Qatar Airways and Lufthansa, which have flights to Iran.

Kayak’s flight-search results for Iran will not include airlines that U.S. companies are barred from doing business with, Cafferty says.

For example, OFAC bars U.S. companies from doing business with Iran Air, Iranair Tours, and Mahan Air.

Priceline itself has never listed flights to Iran, Cafferty says, and that isn’t changing.

Meanwhile, other U.S.-based online travel agencies take a varied approach to Iran itineraries.

CheapOair and Travelocity offer flights to Iran while Expedia, Orbitz and Priceline don’t.

Chris Chiames, a spokesperson for Orbitz Worldwide, says the U.S. Treasury Department several years ago issued restrictions on doing business with certain companies in Iran.

“We haven’t been selling travel to Iran across any of our brands (including Europe to Iran on ebookers) since that time,” Chiames says.

This means, of course, that Orbitz, Expedia and Priceline aren’t displaying flights to Iran even for airlines that don’t make the U.S. sanctions list.

A spokesperson for CheapOair, meanwhile, says it offers flights to Iran in the interest of being comprehensive. Its itineraries to Iran include flights from Alitalia, Qatar, United, Lufthansa, American, Swiss, and Turkish airlines, for example.

“CheapOair strives to have the maximum offer for its customers, who travel to all corners of the world,” the spokesperson says. ?As long as travel is not embargoed it tries to offer as many destinations as possible.”