I can only assume we are being facetious here.
Best war movies are difficult to categorize as they run the gamut of human experience.
IMHO, Saving Private Ryan had some of the best special effects which probably placed the movie watcher in the theater in the experience of the battlefield, without, of course, the added element of fear or courage in facing real life threatening adversity with unknown outcome. It gave a feel of being downrange with impacts landing around your position.
Very few soldiers, sailors, airmen, or Marines fought in more than one Operation during the World Wars due to logistics and casualty rates, so in some respects, Catch-22 was a more accurate war film.
The Longest Day, Tora, Tora, Tora!, Midway and In Harm's Way helped communicate the perspective of the war from both sides when they were made,...to a limited extent, as does Clint Eastwood's recent film about Iwo Jima.
Best war films?
“Gettysburg” is excellent. A good historical drama all round in fact.
“Battle of Britain” is flawed, but has very good air combat sequences (done by pilots who flew in the real thing)
The German film “Das Boot” is the best submarine film of all time, without question, although the series was even better.