See a copy of the letter (PDF Format) sent to US Senator John McCain listing 38 reports the Defense Intelligence Agency (DIA) worked on with Advanced Aerospace Threat and Identification Program (AATIP).

Maybe the actual reports will be release one day.
Many of the listed topics are real eye openers.
18. Metamaterials for Aerospace Applications
19. Warp Drive, Dark Energy, and the Manipulation of Extra Dimensions
25. Space-Communication Implications of Quantum Entanglement and Nonlocality