The oxygen tanks in the movie are actually the scream canisters used in Monsters, Inc.
At around the teasers thirty-three second mark, when Buzz's Cool Starship is entering space, you can see the Pixar lamp in the background as a constellation of stars
When doing his mission logs, Lightyear says the same recurring line from the Toy Story movies when landing on another planet: "Buzz Lightyear to Mission Log. There appears to be no sign of intelligent life anywhere." Every instance of this line is also interrupted in some way.
The ship's internal voice activated navigator (IVAN), the equivalent of a GPS, acts like a real-world, misbehaving GPS. It's voiced by Mary McDonald-Lewis who's also the voice of OnStar's navigation system.
The Space Ranger suit that Darby wears throughout the film reads "Tempus". This is a reference to "Tempus from Morph", one of the names being considered for Buzz Lightyear early in development of the original Toy Story (1995). The "Tempus from Morph" name was used in the 1992 test footage for that film.