Two US lawmakers with antitrust oversight advised the Obama administration to review the planned merger of American Airlines and US Airways Group carefully. This is to ensure that the prices for air travelers will not increase dramatically.

On February 14, US Airways made an announcement to buy American Airlines, the parent of AMR Corp. that is restructuring in bankruptcy court. The deal is said to be in full completion by the end of September this year.

Chairperson for the Senate Judiciary Committee, Senator Amy Klobuchar along with top Republican Mike Lee said that the deal would lead to the top four US airlines controlling 90% of the US market.

On a letter dated Tuesday, the two acknowledged that efficiencies associated with the deal are to be seen. However, they also noted issues about flight costs could increase or customer service could decrease.

Late last May, more than one hundred Congress members asked the US regulators to allow American Airlines and US Airways Group to keep all their airport slots at Reagan National if the merger pushes through.