A budget airline that serves mostly small U.S. cities began federal deportation flights Monday out of Arizona, a move that’s inspired an online boycott petition and sharp criticism from the union representing the carrier’s flight attendants.

Avelo Airlines announced in April it had signed an agreement with the Department of Homeland Security to make charter deportation flights from Mesa Gateway Airport outside Phoenix. It said it will use three Boeing 737-800 planes for the flights.

The Houston-based airline is among a host of companies seeking to cash in on President Donald Trump’s campaign for mass deportations.

Congressional deliberations began last month on a tax bill with a goal of funding, in part, the removal of 1 million immigrants annually and housing 100,000 people in U.S. detention centers. The GOP plan calls for hiring 10,000 more U.S. Immigration and Customs Enforcement officers and investigators.

Avelo was launched in 2021 as COVID-19 still raged and billions of taxpayer dollars were propping up big airlines. It saves money mainly by flying older Boeing 737 jets that can be bought at relatively low prices. And it operates out of less-crowded and less-costly secondary airports, flying routes that are ignored by the big airlines. It said it had its first profitable quarter in late 2023.

Andrew Levy, Avelo’s founder and chief executive, said in announcing the agreement last month that the airline’s work for ICE would help the company expand and protect jobs.

“We realize this is a sensitive and complicated topic,” said Levy, an airline industry veteran with previous stints as a senior executive at United and Allegiant airlines.

Financial and other details of the Avelo agreement — including destinations of the deportation flights — haven’t publicly surfaced. The AP asked Avelo and ICE for a copy of the agreement, but neither provided the document. The airline said it wasn’t authorized to release the contract.

Several consumer brands have shunned being associated with deportations, a highly volatile issue that could drive away customers. During Trump’s first term, authorities housed migrant children in hotels, prompting some hotel chains to say that they wouldn’t participate.

Avelo was launched in 2021 as COVID-19 still raged and billions of taxpayer dollars were propping up big airlines. It saves money mainly by flying older Boeing 737 jets that can be bought at relatively low prices. And it operates out of less-crowded and less-costly secondary airports, flying routes that are ignored by the big airlines. It said it had its first profitable quarter in late 2023.

Andrew Levy, Avelo’s founder and chief executive, said in announcing the agreement last month that the airline’s work for ICE would help the company expand and protect jobs.