Sure the physics of the flight were real as they were flying real aircraft.

However, it is against the air forces rules to fly so closely in formation. CGI was used to bring the jets closer together to look better on camera. The majority of the environments were CGI as they were not permitted to fly so close to the ground or obstacles. The entire opening sequence with the advanced fighter jet was entirely CGI as that plan does not exist. That's what CGI looks like when you have the means, time, and budget. Plus combining that with practical effects, leads to the best results.