TAP Air Portugal hopes for strong demand from the US this summer. There's just one big obstacle.

It's been a difficult pandemic for TAP Air Portugal, as it's been for all airlines that rely on long-haul international travel. However, CEO Christine Ourmières-Widener believes things are finally looking up.

Ourmières-Widener, who was appointed in June, will head the airline through what many expect will be the first proper transatlantic summer travel season since COVID-19 brought the world to a halt.

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"We see some ramp up," Ourmières-Widener told TPG last month during a video conversation. She said that the airline had flown roughly 80% of its 2019 capacity around the holidays, and expected to fly "at least" the same level for the summer.

Part of Ourmières-Widener's optimism comes from the fact that restrictions have started to loosen, with local jurisdictions and national governments lifting mask requirements, rules for visitors to file locator forms for contact tracing and more. Countries have even lifted testing requirements, no longer requiring vaccinated visitors to present a negative test before departing or upon arrival.

Still, the U.S. has been a conspicuous outlier, keeping travel requirements— which were tightened during the omicron surge — in place. Everyone traveling to the U.S. by air, regardless of residency or vaccination status, must provide a negative test.

Despite her optimism for the summer, Ourmières-Widener said that the U.S. testing requirement creates a particular challenge: Americans who may feel comfortable traveling again could be dissuaded by concerns over getting stranded abroad.

"It's uncertainty," Ourmières-Widener said. "Will I be stuck in my destination if I test positive on the way back?"

It's unclear whether the U.S. will lift the requirement by the summer. Aviation and travel industry representatives have lobbied the Biden administration, unsuccessfully so far, to end the policy. Meanwhile other countries lifting requirements — even as cases of the BA.2 omicron sub-variant spread across Europe — could exert pressure on the U.S., particularly if rising cases do not overwhelm healthcare systems like previous waves.

Read more: Senate says airplane mask mandate needs to end; will it?

In January, the federal government issued a 90-day extension of the public health emergency declaration surrounding the pandemic. The PHE designation is currently slated to lift on April 16 — two days before the federal mask mandate expires — and it's unclear whether it will be extended or what impact its lifting would have on travel restrictions lined to the pandemic.

Nevertheless, whether the testing requirement remains in place or not, Ourmières-Widener sees strong potential for this summer, particularly given the carrier's competitiveness for connecting passengers traveling elsewhere in Europe.

"Portugal is a great destination, it's a great country," she said. "I think probably we'll have the same mix between point-to-point and connecting."