An employee rally is planned for Capitol Hill to cap off the lobbying push. The airlines are also sponsoring a letter-writing campaign, encouraging their 108,000 combined employees to send pre-written emails to elected officials expressing their support for the merger. As of Friday, US Airways said employees had sent nearly 75,000 messages.
Some lawmakers have said they disagree with the DOJ and encouraged the agency to drop its lawsuit.
"This is yet another attempt by the administration to stifle business and free enterprise and instead create needless government over-regulation," Texas Rep. Michael Burgess, a Republican, said in a letter earlier this month to U.S. Attorney General Eric Holder.
Employees who are planning going to lobby this week said they hope lawmakers will pressure the DOJ to settle with US Airways and American quickly and head off a trial.
"Anytime you can settle something, it would be great," said Bossi, of the flight attendants group.
The airlines and many of their employees say that combining the No. 3 and No. 5 carriers, American and US Airways, would actually create a more competitive environment by giving United and Delta Air Lines a third mega-competitor.
More than 7,400 US Airways employees are based in Charlotte, the airline's busiest hub. After the American merger, Charlotte would be the combined carrier's second-busiest hub, behind Dallas/Fort Worth.
US Airways, as the smallest of the so-called legacy carriers, has traditionally paid its employees less than industry average wages in order to stay competitive. One of the major selling points for the merger to employees was the promise of higher wages and a more stable career, along with no job cuts for non-corporate employees.
Airline employees have also endured thousands of layoffs as US Airways, American and every other legacy airline went through bankruptcy since 2001.
A federal bankruptcy court judge has approved American's merger plan with US Airways, and the Justice Department challenge is now the only remaining hurdle.
The Justice Department also opposed the 2001 US Airways-United merger, which soon fell apart. But the agency didn't oppose the 2008 Delta-Northwest merger, the 2010 merger of United and Continental, or Southwest's acquisition of AirTran in 2011.
Some airline employees say that feels personal. "You can't combine all these guys and then say stop," said Bossi. "This is the second time they've done it."
Arizona, Florida, Pennsylvania, Tennessee, Texas and Virginia, D.C. and Michigan have also joined the Justice Department in its lawsuit.
Roger Holmin, Association of Flight Attendants president, said he plans to tell lawmakers that blocking the merger will hurt employees.
"The DOJ has basically declared war on workers," said Holmin, who is based in Philadelphia and has an office in Charlotte. He's also meeting with state attorneys general, including those of North Carolina, Tennessee and Pennsylvania.
The request for more information is the latest move in the legal wrangling ahead of a planned Nov. 25 trial on the merger.
Association of Professional Flight Attendants says the Association of Flight Attendants wants to throw away months of negotiations and force a battle over representation.