The requirements for doctoral programs vary from university to university. However, you must have a master's degree in the field of interest before you can consider a doctoral program.
That is strictly dependent on the school. Most of the schools I have been involved with require a minimum of a 2.5. However, this is not to say others might not be higher.
You must have a bachelor's degree in engineering, biological science, physical science, or mathematics. At least 1,000 hours pilot-in-command time in jet aircraft. Flight test experience is highly...