Unlike previous Spider-Man movies, Spider-Man: Homecoming didn't feature just Peter Parker as the only superhero. While Tom Holland's iteration was the one fighting evildoers (as it should be), he was also joined by his mentor, Tony Stark, a.k.a. Iron Man. Tony's inclusion was understandable given how he bonded with Peter last year in Captain America: Civil War, and thankfully he didn't overshadow Spider-Man. But at one point, the Spider-Man: Homecoming team was thinking about giving Peter some extra superhero company by including War Machine and Vision.
Warning: SPOILERS for Spider-Man: Homecoming are ahead!
Approximately halfway through Spider-Man: Homecoming, Peter Parker found himself in quite the pickle when one of the weapons used by Adrian Toomes' gang malfunctioned and split a Staten Island ferry in half. Peter tried desperately to keep the boat intact with his webbing, but he was unsuccessful, and it was only thanks to Iron Man's timely intervention that everyone on board was saved. As you can see in the above artwork from Spider-Man: Homecoming - The Art of the Movie (via MCU News & Tweets), it was considered having War Machine and Vision aid in the rescue mission, with Vision snagging one of the falling cars and War Machine peeling off part of the hull to presumably reach some occupants.
The Marvel Cinematic Universe has shown more willingness in recent years to throw superheroes into solo movies led by other protagonists, from Falcon fighting Scott Lang in Ant-Man to Hulk being a supporting character in Thor: Ragnarok. However, since Iron Man already filled such a position in Spider-Man: Homecoming, it's probably for the best that War Machine and Vision didn't cameo. Spider-Man: Homecoming had enough Avengers ties, and throwing those two into the ferry rescue would have been overkill. Besides, given that Spider-Man: Homecoming takes place only a few months after Captain America: Civil War, it's hard to imagine War Machine being out in the field since he was paralyzed and having difficulty using Tony Stark's bionic leg support when we last saw him. Going from that to rescuing civilians in that bulky armor is a stretch.
For those of you itching to see War Machine and Vision back in action, your wish will be granted soon. Both of them are confirmed to return in Avengers: Infinity War next year. Vision will be especially important to the story because the Mind Stone in his forehead is one of the six Infinity Stones Thanos is desperate to obtain. As for War Machine, we'll have to wait and see whether he's well enough to return to his superhero duties or if he'll stay on the sidelines.
Spider-Man: Homecoming is now playing in theaters, and Spider-Man: Homecoming 2 is scheduled for release on July 5, 2019.
