Gliding for 150 ft continuously requires the grapnel boost IMO. I'm sure it's not officially required but I found that it was much easier to achieve once I did the first 4 AR Training missions and got the grapnel boost. Also, I think a decent understanding of dive bombing and pulling back during gliding is essential. It allows you to essentially stay afloat forever as long as you don't have to navigate through too many buildings and such.
If you're talking about flying through those green loops, like in the AR challenges, then I'm afraid I don't have much advice to give other than keep at it and you will get it through perseverance and focus.
Above all... BE the Batman.