Does the airline pay for a hotel if my flight is cancelled?

It depends on WHY the flight was cancelled. For "controllable" cancellations — mechanical problems, crew issues, IT outages, operational decisions — most major U.S. airlines commit to providing hotel accommodations when the cancellation results in an overnight stay. This is part of their customer service plans filed with the DOT.

For weather cancellations and air traffic control issues ("uncontrollable" events), airlines are NOT required to provide hotels, meals, or additional compensation. They must rebook you on the next available flight, but lodging is on you. This is the most common complaint travelers have, and it's a genuine gap in U.S. consumer protection compared to European rules.

How to tell the difference: if only your airline's flights are cancelled while other airlines are still flying the same route, it's almost certainly controllable. If all airlines at the airport are affected, it's likely weather/ATC. Check the FAA's airport status page or Flight Check's delays-today page. When seeking a hotel voucher, ask the gate agent firmly but politely, reference the airline's customer service commitment plan, and if denied, escalate to a supervisor. Document everything — a DOT complaint with documentation is your strongest leverage.