ATLANTA — Six Democratic senators want to tax any U.S. airline that wants to charge passengers for their carryon bags.

The legislation announced Wednesday comes after a small Florida airline, Spirit Airlines, said recently that it plans to begin charging its customers as much as $45 to bring a bag aboard its aircraft and put it in an overhead bin.

Air travelers have been forced to pay a barrage of fees for once-free amenities since 2008. Critics say charging for carryon bags is stepping over the line.

The legislation would designate carryon baggage as a necessity for air travelers, and force airlines to pay a tax on that revenue.

The senators argue this would keep more airlines from following Spirit’s lead.