Travel by airplane is on the rise, with average daily volumes at Seattle-Tacoma International Airport steadily increasing since its low point in March. But there’s a long way to go.

Airlines are working hard to reassure passengers about their coronavirus-conscious policies, but in practice these turn out to be not simple to implement and police. That could put a damper on air travel, especially leisure trips.

Meanwhile, airlines are restoring some flights. Delta said this week it is resuming a Seattle-Shanghai route, stopping in Seoul. It’s the first airline to return to regularly scheduled U.S.-China flights, which were suspended in February.