Some business travelers are keeping cars up to seven days, compared with less than three days before the pandemic. They are driving distances — like from St. Louis to Chicago — that they previously flew, Mr. Moore said.

Recent polls also raise questions about the timing of a rebound in business travel and its possible replacement by virtual meeting platforms. In a survey by Institutional Investor magazine last month, more than half of the chief information officers, portfolio managers and other investment decision makers said they did not expect to travel again until November and December, at the earliest. And 93 percent of the more than 300 global companies surveyed in May by the BCG Henderson Institute, the research organization of the Boston Consulting Group, expected to permanently change “remote-working and meeting policies,” while 66 percent anticipated permanently changing travel policies.

Typical of the people who would normally be traveling for work but aren’t is Erin Eckert, director of the infectious-disease portfolio at the nonprofit organization RTI International in Washington. Before the pandemic, she spent about a quarter of her time traveling for malaria-related research across Africa. Now she is grounded indefinitely, working out of her home.

Then there are self-employed business travelers whose visits to clients’ offices have been suspended, like Paul Grizzell, an organizational consultant in Woodbury, Minn.

Mr. Grizzell, who used to spend three weeks each month visiting clients, mostly in the United States, hasn’t traveled since late February, he said. Instead, he has been working with clients remotely on Zoom, which, he said, “is not the same as being in a conference room with a team of people, working on a business problem, eating lunch together, catching up on family.”

He hopes to resume his domestic business trips this summer and international travel “maybe in December or January,” once his clients return to their offices.

Among the challenges with resuming business travel are the varying guidelines put out by airports and airlines. For companies to be comfortable sending employees on business trips, “there have to be somewhat consistent, clearly communicated guidelines,” said Mike Janssen, global chief operating officer and global chief commercial officer of BCD Travel, a travel management company.