not have credit card find difficult book airline ticket online
not have/credit card/find/difficult/book/airline ticket/online
A. Although I didn't have credit card, I found difficult to book an airline ticket online.
B. I don't have a credit card, I found it difficult to book an airline ticket online.
C. Not having a credit card, I found it difficult to book an airline ticket online.
D. As I don't have a credit card, so I found it difficult to book an airline ticket online.