Airlines are tightening face mask rules three months after making masks mandatory onboard.

Most major airlines have eliminated medical exemptions to the rule, and several are cracking down on the types of face coverings allowed. Passengers who refuse to wear masks will generally be denied boarding and might be prohibited from flying the airline again. Delta said it's banned about 130 passengers to date, and Alaska says it will cancel any connecting flights or return flights for travelers who refuse to wear a mask in flight.

All airlines are insisting passengers wear a mask as soon as they step into the airport and to keep it on throughout the travel journey, except to briefly remove to drink or eat.

Read the full article at USA TODAY