[Veto!]

We are told not to worry because it takes close contact with an infected person to catch it, but now everybody who knows someone on the plane is at risk?

Yeah, don't worry; be happy.

How quickly to symptoms manifest? Might someone bump into an infected person in an airport elevator and catch the disease even tho the carrier didn't yet know he was ill?

[wrench]

“How quickly to symptoms manifest? Might someone bump into an infected person in an airport elevator and catch the disease even tho the carrier didn’t yet know he was ill?”

It would appear so. An infected person is contagious before symptoms are present.

And if you read the link from B.A. above, it also looks like a cough or sneeze can transmit the disease, the recipient collecting the virus in the lungs and airways.

[IYAS9YAS]

How quickly to symptoms manifest?

CDC says anywhere from 2 to 21 days, with the average being 8 to 10 days.