The $11 billion all-stock deal, announced on Thursday, would create the world's largest air carrier.

"I plan to hold a hearing to thoroughly review the proposed merger and examine its impact on competition and consumers," said Amy Klobuchar, the Minnesota Democrat who chairs the Senate Judiciary subcommittee that considers antitrust, competition policy and consumer rights.

No date has been set for a hearing so far.

Mike Lee of Utah, the ranking Republican on the Senate antitrust subcommittee, said the planned merger could benefit consumers and the air travel industry, but "poses potential risks for the market" following years of airline consolidation.

"Antitrust officials must ensure that an additional merger of this magnitude would not lead to higher passenger fares, result in diminished service to regional markets, or allow for coordinated conduct among rivals," Lee said.