To make Buck appear frozen in his space shuttle he was sprayed all over with an ordinary dry shampoo. Because of this he couldn't open his eyes or move, so while he was waiting for them to shoot the scene he supposedly fell asleep.
To cut costs, some footage and various props were used from Glen A. Larson's Battlestar Galactica (1978) series. Even some of the concept designs from Galactica were used. The Terran starfighters on Buck Rogers were originally designed as the Colonial Vipers for Galactica, but Larson had opted for a design closer the X-Wing fighters from Star Wars: Episode IV - A New Hope (1977). Larson then employed the unused designs for Buck Rogers.
The 90 minute theatrical film was the pilot for the TV series Buck Rogers in the 25th Century (1979), but was shown in theatres several months before the series aired. It made over $21 million in North America alone.
The Buck Rogers theme features lyrics that were not used for the TV series. It has been noted that these lyrics seem to parallel plot developments in the later Buck Rogers-inspired series Farscape (1999).
Originally, Twiki was just going to make unintelligible electronic noises (the "biddi-biddi-biddi" sound) and Dr. Theopolis was to act as his translator, but it was deemed to be too similar to R2-D2 and C-3PO from Star Wars: Episode IV - A New Hope (1977) and so Twiki was given a voice of his own.
Kane's back story was that he was a former student of Doctor Huer's who defected to the Draconians and to act as consort/advisor for Princess Ardala, the chief antagonist of the series. In the original 1930s movie serial of Buck Rogers (1939), "Killer Kane" (as he was known) is actually a powerful gangster from Earth and is the chief antagonist of the story. Princess Ardala was not featured in the 1939 movie serial.
In the original ending for this film, Buck and Wilma celebrate the victory over Ardala and Kane by dancing to the tune of "Chicago, Chicago, that toddling town." This last scene was entirely cut and the film now ends with Buck and Wilma returning to Earth by starfighter.
Why there are two different Tigermen in the original film? According to costume designer Jean-Pierre Dorleac, it's because the fight scene between Tigerman and Buck was added later, after the original production had already wrapped. When they tried to call the actor who had played Tigerman earlier in the film back (he'd been "discovered" for the part on the Universal Studios back lot tour), they couldn't find him! So they had to replace him with a lookalike (who, frankly, didn't).