U.S. Bankruptcy Judge Sean Lane said in a short statement that the reasons for the denial were listed in a 32-page opinion dated Nov. 27.
"For those same reasons, the plaintiffs' motion seeking a stay pending appeal is denied," Lane wrote.
The motion was filed by attorney Joseph Alioto on behalf of 40 clients, the Dallas Morning News reported Thursday.
Alioto argued that a delay would do no harm, but the merger would create "irreparable damage" to his clients.
At a Nov. 27 hearing, the airlines disagreed, stating a delay in the merger would be irreparably harmful to them.
Barring any unforeseen surprises, there will be a new airline by Monday morning called American Airlines Group.
The merged company is expected to be listed on the Nasdaq exchange Monday morning, the News said.
ATM fees on the rise, again