I saw this film when it first came out in 1963, a few months after the Cuban Missile Crisis. I lived near a SAC base in south Florida, had a lot of friends whose fathers were USAF, and found the realism of the film rather scary. Seeing it again more recently, I was still impressed with the storyline and the semi-documentary footage of the B-52s and KC-135s.
The deficiencies of this film are those of most Hollywood films of the 1950s (or the "greater 1950s" in this case): star casting and "love interest." Rock Hudson was never a great dramatic actor (one exception: John Frankenheimer's "Seconds"), although he's obviously working hard here to convince you that he's a decent guy whose job as a SAC wing commander requires him to be a "heel" at times. His lack of credibility has nothing to do with his homosexuality (in hindsight) and everything to do with the image that Hollywood crafted for him in the 1950s. Rod Taylor played a lot of macho roles but he also struck me as a little too precious in this film, cast mainly as a romantic rival for his boss's wife. She's played by Mary Peach, and her thankless role requires her to display considerable initial ignorance of the strains on a military officer's family. Since this is as much a character study as it is an "occupational" movie, the interaction between Col. Caldwell and his wife is an important part of the film. But it would have been more interesting if they were portrayed as a long-married couple than a pair of newlyweds. The "lesser" roles in the film, however, feature some convincing performances by such Hollywood characters as Barry Sullivan, Leora Dana, Kevin McCarthy, Richard Anderson, Henry Silva, and Nelson Leigh.
I had not realized until a recent viewing that Sy Bartlett both produced and wrote the original story for "A Gathering of Eagles." I have long been a fan of Barlett's novel "Twelve O'Clock High" (co-written with Beirne Lay Jr.) and its classic film version, released in 1949, directed by Henry King and starring Gregory Peck and Dean Jagger. And as I watched "Gathering" I quickly realized that Bartlett was telling essentially the same story as "Twelve O'Clock High," updated from the World War II Eighth Air Force to its Cold War successors in SAC, about the soul-grinding responsibilities of command. The B-17s become B-52s, and Peck's Gen. Frank Savage becomes Hudson's Col. Jim Caldwell, but both characters face the same hard challenges, preparing men and machines for war by imposing high standards and hard discipline. The main difference is in that "love interest" subplot, but again, that would be more appropriate for a film set in Cold War "peacetime."
Of course, there were a couple of moments in the film when I had the feeling that Col. Caldwell would stress out to the point that he would become General Jack D. Ripper. Interesting double-feature possibility there, coupling "Gathering" with "Dr. Strangelove."
Interestingly, the best performance in "Gathering" is that of Robert Lansing, who plays a career USAF non-com with a quiet gravitas that characterized much of this under-rated actor's career. About a year or so after "Gathering" was released, Lansing traded his non-com's uniform for officer's pinks and took on the role of Gen. Frank Savage in the TV series based on "Twelve O'Clock High." I haven't seen those programs in many years but I recall the disappointment I felt when Lansing quit after one season. Good actor, good role.
Conclusion: "A Gathering of Eagles" is in many ways a relic of its times, the early 1960s, when Cold War tensions were at their their tautest and nuclear war seemed a tremendous threat. Actually, compared to earlier films with similar backgrounds (e.g., "Strategic Air Command" and "Bombers B-52"), "Gathering" doesn't say much about the Cold War or about justifying SAC. Given what they had experienced in the preceding months, 1963 audiences didn't need that background info; and the fear or nuclear war may have contributed to this film's poor box office performance. Who needed the reminder?
Did SAC help win the Cold War (by deterring a Soviet nuclear attack and making the U.S.S.R. spend billions for its own defense)? There's no way to know for sure, but there's a case to be made for that argument. This film is an inkling of just how difficult the job was.