Overall production was great. There was very little noticeable CGI, they used miniatures extensively and all the in-aircraft shots were filmed in motion-simulators in front of a massive LED wall that apparently made most of the crew ill. Gosling was even coached by an X-15 pilot on what buttons to push during filming.

https://youtu.be/wZEcwrBcqGs?t=42 (see also about 8:40)