Ihraam

Performing Salaatul ihraam in the airport and making the intention of ihraam before approaching the Meeqaat

Q:

1. Can a person make his salatul ihraam e.g. at JHB Airport and only make his niyyat before approaching the miqaat when flying on Saudia Airways for umrah?

2. Similarly, can a person make his salaatul ihraam at Dubai Airport and only make his niyyat as approaching the miqaat when flying Emirates?

3. When landing in Dubai, it is already fajr time, we made salaatul ihraam and thereafter read fajr salaat because we had to leave for Jeddah. Is it Ok to read salaatul ihraam in fajr time, before we read fajr. If not, how should it be done?