Published: Apr 13, 2010 11:34 PM EDT

WASHINGTON - Spirit Airlines is encountering opposition to its decision to charge $45 per carry on bag. Lawmakers are opposing the plan. New York Senator Chuck Schumer called it a "slap in the face" to travelers, while the Transportation Secratary Ray LaHood is threatening to halt the measure.

Spirit Airlines, on the other hand, argues that the baggage fees keep airfare prices lower, while saving time for travelers. Spirit is reportedly offering priority boarding to travelers who pay for carry on bags.

The new carry-on baggage fee will go into effect on August 1.