Ask Ur doctor once. 
Some air flights doesn't allow pregnant women in eight ninth month ..plz read their policy and tell them in advance before planning air travel .. 
Train journey is also safe but it's long (15hrs). .. 
U must take advise from Ur gynae. As per ur condition in 35th week , she can suggest better.

Hi 
Both are safe but check with your gynecologist and plan the travel schedule

I have to travel in my 35th week ,,which is safe to travel train or flight? Tain will take 15hrs and flight will take 1.5hrs.so which is safe to travel??