It took me over 8 minutes to get this bomber delivery ribbon. I wasn't playing this round as a good squad mate either. I went directly for the bomber, switching to whichever squad was closest to the bomber door at every opportunity.
This is actually the very first bomber delivery ribbon I got, but I couldn't get the video to upload correctly from my PS4 until now. Its pretty obvious I didn't know what I was doing with the bomber in this video and I lucked out with an assist counts as kill in the end. Check my other bomber videos to see better kills. The main thing with the bomber is to target stationary vehicles and infantry.