Gemini 4

4 declassified cases mention this

• PDF · 1998USG-UAP-D001, Congressional, White House, UFO-related Constituent Correspondence, 1998
• PDF · 1965NASA-UAP-D016, Preliminary Gemini 4 Crew Debriefing, Part I, 1965
• PDF · 1965NASA-UAP-D017, Preliminary Gemini 4 Crew Debriefing, Part II, 1965
• PDF · 1965NASA-UAP-D018, Gemini 4 Experiment Debriefing, 1967