Barred from coming in 2020 when the COVID-19 pandemic was raging across the world, American tourists who have been vaccinated or can show negative tests will be allowed to return, and more airlines are already offering flights.

United Airlines said it would begin seasonal daily service to Iceland and Greece beginning in July, the move coming after Delta earlier said it would resume flights from JFK Airport in New York City to Athens in June.

Greece now allows travelers from the European Union, United Kingdom, United Arab Emirates and also the US but the doors won't open wider to other countries until May 14 and direct flights for United and Delta not until the summer.

Both Greece and Iceland are heavily dependent on tourism dollars. Tourism constitutes about one-tenth of Greece's economy, and those revenues plummeted 80% as a result of the pandemic, The National Herald reported. 

Greek-Americans especially are eager to get back to the homeland after being shut out a year earlier and Greece's New Democracy government is hoping vaccination programs and health protocols will convince people it's safe.

United Airlines separately posted a $1.36 billion loss in the first quarter and will need a rebound in lucrative business and international travel before it returns to profitability.

The loss reported Monday would have been even wider without federal payroll aid, but it was still slightly worse than expected. However, investors are far more interested in how quickly United and other airlines can recover from their pandemic-caused financial crisis.

United executives have said recently that bookings are rising ahead of the peak summer vacation season, and they expect that trend to grow stronger as more Americans get vaccinated against COVID-19. The airline predicted that a number of financial measures will improve from the first quarter into the second.

Still, United and rivals American Airlines and Delta Air Lines depend on high-fare business and international travelers for an outsized share of revenue, and nobody knows exactly when those customers will come back. 

However, also on Monday the State Department urged Americans to reconsider foreign travel and said it will label about 80% of the world's countries as "do not travel" destinations because of COVID-19 risk. 

United executives declined to comment until talking to analysts on Tuesday. CEO Scott Kirby said in a statement that executives "now see a clear path to profitability. We're encouraged by the strong evidence of pent-up demand for air travel" and can match it to meet targets for a financial recovery.

Leisure travel within the U.S. is approaching pre-pandemic traffic, but business and international travel remain deeply depressed.

United said in a news release that it turned cash-flow positive in March, excluding certain costs, but it won't be profitable on a normal accounting basis until business and long-haul international travel return to 65% of their 2019 levels. It did not offer a forecast for when that might happen.

Kirby said this month that business travel is only 20% of normal. United's revenue from first-quarter international flights was down just 18% of the total in 2019, and that figure is propped up by stronger traffic to Mexico and the Caribbean. 

United Airlines will be smaller when it emerges from the pandemic. Like other U.S. carriers, United convinced thousands of employees to leave voluntarily — the terms of federal aid prohibited furloughs — and it aims to cut permanent costs by $2 billion a year.

Chicago-based United's first-quarter loss was narrower than a year ago, when it lost $1.70 billion. The airline earned a profit of $292 million in the same quarter of 2019.

Without payroll relief from taxpayers and other temporary items, United would have lost $2.45 billion, or $7.50 per share. Analysts surveyed by FactSet expected a loss of $7.08 per share. 

United previously disclosed revenue of $3.22 billion, a 60% drop from a year earlier and 66% lower than two years ago.

Cargo was a bright spot, nearly doubling from a year ago. Like other carriers, United took advantage of space in the bellies of its planes to carry more goods. Still, cargo accounted for only 15% of United's revenue, a share that is likely to gradually decline over the next several quarters as air freight is replaced by passenger bags.

Shares of United Airlines Holdings Inc. fell about 2% in extended trading after the release of its earnings report. They closed Monday's regular session down 1.6%.