To have an air dragon u should have a proper water and a fire dragon (no hybrids/mixtures). Sent them to the breeding cave. Select water dragon on the left and fire dragon on the right. U will get an air dragon in 2 hours after breeding. After getting an air dragon send air and fire dragon to the breeding cave and u will get a blazing dragon. Send cold and blazing dragon to the breeding cave and in 48 hours after breeding u will get a rainbow dragon.