First face masks and now health questionnaires.

United Airlines on Wednesday became at least the second U.S. carrier to ask travelers to answer questions about their health status before they fly. It’s all part of a strategy to ease the mind of travelers concerned about flying in the midst of the novel coronavirus pandemic.

United’s “Ready-to-Fly” checklist will ask travelers to confirm that they have not experienced any coronavirus-related symptoms in the 14 previous days or been in close contact with any individual who has tested positive during the same time period. It also will require passengers to verify that they are aware of the airline’s policy, which requires face coverings when onboard an airplane.

“The health and safety of our customers and employees is our highest priority, and we have been working closely with trusted medical experts and partners to institute new practices and procedures to further protect those who work and travel with us,” said Pat Baylis, corporate medial director for United. “United’s ‘Ready-to-Fly’ wellness checklist sets clear guidelines on health requirements for our customers and helps minimize the risk of exposure during the travel experience.”

United has partnered with the Cleveland Clinic on health and safety issues related to the novel coronavirus and its disease, covid-19.

In April, Frontier Airlines became the first U.S. airline to ask passengers to fill out a health questionnaire and earlier this month, it began doing temperature scans of all passengers before boarding. Those with temperatures of 100.4 or higher will not be allowed to board the plane.

United passengers will be required to click “accept” to verify that they reviewed the checklist when they check in on the United mobile app, at United.com, at a United kiosk or with an agent at the airport before they receive their boarding pass.

U.S. airlines also recently began requiring passengers to wear face masks when on board airplanes. However, at a House Transportation Committee hearing Tuesday, several lawmakers who had recently flown said not all travelers appeared to abide by the rule.

Rep. Alan Lowenthal (D-Calif.) said it was frightening flying through an airport near D.C. because of the crowding and because “half the people weren’t wearing masks.”

Susannah Carr, a United flight attendant who testified on behalf of the Association of Flight Attendants-CWA, said it has been difficult for some crew members to enforce the rule because, unlike smoking or other infractions, it’s not a violation of law if customers refused to wear a face covering.