Not sure what you mean by "the theory." Ebola is not airborne. It's relatively easy to isolate in areas with good hygiene and medical care.
I'm only aware of these cases (are there others?) Hence, I used theory until you've had a few more occurrences.
The first link in the previous comment documents:
1) 1996 a man in Gabon travelling to Johannesburg and he didn't infect anyone.
2) 2004, a man with Lassa fever, similar to Ebola, travelling to the US and not infecting anyone.