I'm looking at the entry requirements for the UAE for US citizens;

- Passport valid for more than 6 months
- Roundtrip ticket

How do I provide proof of a roundtrip ticket if I'm flying SYD-AUH (on Etihad) then DXB-LHR on Qantas? I won't be able to get my Qantas ticket until I checkin at DXB.

Will a printout of my e-booking be sufficient?

Thanks in advance.