i saw this proposal a few years back, fom memory a new junction cuts of the exsisting 7 somewhere near to the toll booth, then heads across the army/navy land raise up in the air, which accounts for the price, it then crosses sukhumvit road near to 332 road and into the front of the airport
here is a link from 2022 - https://thepattayanews.com/2021/11/04/2-kilometer-long-road-connecting-motorways-to-u-tapao-airport-planned-to-reduce-traffic-starting-in-2022/