I noticed a possible disc on a documentary-Golden Gate Bridge

[Hauntedman]

★★★ UFO disc flies thru Golden Gate Bridge caught on documentary film!!! Must see ✔

I discover what appears to be an anomalous silver disc UFO craft flying through Golden Gate Bridge on the documentary film, The Bridge (2006), directed by Eric Steel. I sent a tweet to the director saying he should check it out. What do you think? Is it really an optical illusion or it is a real UFO?!

The film director responded to me and says he think it could be a helicopter. What do you think?

As far as aircraft being able to fly below the bridge: According to 91.119
Except for takeoff or landing, no person may operate an aircraft below the following altitudes;
a. Anywhere. An altitude allowing, if power unit fails, an emergency landing without undue hazard to persons or property on the ground.
c. Over other than congested areas. An altitude of 500' feet above the surface, except over open water or sparsely populated areas. In those areas the aircraft may not be operated closer than 500' to any person, vessel, vehicle, or structure.
https://youtu.be/IHkFQj8JNm0

[Hauntedman]

Some have mentioned insect though it appears to go 'dark' once under the bridge (or as it appears to go). Helicopters are as far as I know not allowed to fly under it-the bridge, especially that close.