" ... ha csak egy repülőgépe van". Otherwise, very good!!
Yes, it should be translated as "has airplanes".
'... az egy nagyon kicsi ország, ha neki csak egy repülőgépe van.' ('van' at the end)
The Hungarian sentence btw means 'The country does have at least one airplane' but it can be 1 or actually even 10000.
Got the same, it must not have been fixed yet. Reported as well. This course, while being good at teaching the language is very inconsistent with the accepted answers :/