U.S. airlines are continuing to beef up their requirements for passenger facial coverings, particularly among those claiming exemptions for medical reasons.

Both Hyatt and InterContinental Hotels Group now require guests to wear face coverings within indoor public areas of its U.S. and Canadian hotels.

The carrier's high-efficiency particulate air filtration system recirculates air in the cabin every 2-3 minutes and removes 99.97 percent of airborne particles, including viruses and bacteria.

U.S. Customs and Border Protection enrollment centers for Trusted Traveler Programs will not reopen until Sept. 8 at the earliest.