Updated: July 12, 2021

The props used in this show, (such as the computers and guns) also were used in Lost in Space, The Time Tunnel, Voyage to the Bottom of the Sea, and "Batman" (1966).

Often dismissed by science fiction "purists" such as Harlan Ellison, because of the sheer physical impossibility of such "giants" possibly existing, as their mass (which would increase geometrically while their strength only increased proportionately) would crush them. The novelization of the series (by Murray Leinster) attempted to account for this. No such explanation is ever given in the series.

At the time of its debut, this was the most expensive show produced on television.

Even though certain cities are named, the name of the giants' planet is never mentioned.

Actress Heather Young, who played stewardess Betty Hamilton, was pregnant for much of the show's second season resulting in her either being filmed mostly from the waist up, wearing baggy outfits or being written out of several episodes altogether.

In one of the last episodes of the series ("Wild Journey"), Steve and Dan travel back through space and time to before they left Earth, and they attempt to change history by persuading any one of their passengers not to take the fateful flight. Actor Stefan Arngrim, who played Barry Lockridge, had entered puberty and could not reprise his younger self, so a body double (with face obscured) was used.

Although it is supposed to be another planet, nameplates visible on cars and trucks on the show clearly indicate they were manufactured by Chrysler Corporation (the automaker contracted with the series studio at that time).

In the second season, devices such as a laser torch and a periscope were used by the castaways.

The flight number for the Spindrift was 612.

The Spindrift, on London-bound suborbital flight 612, crashed on June 12 1983. This date was creator Irwin Allen's birthday.

Throughout the run of the show, the actors performed their own stunts and stunt doubles were rarely used unless it was absolutely necessary.

Although the series ran for two years (1968 thru 1970), the first 12 episodes were filmed in the summer and fall of 1967 to meet the original planned start of the series which would have been January, 1968. The network was originally planning to use "Giants" as a mid-season replacement show. Since nothing needed replacing on their schedule, the series's premiere date was pushed back to Fall 1968 where it inevitably replaced Irwin Allen's "Voyage" series on the schedule. The 1967 start of the series filming helps explain the difference in appearance of actor Stephen Arngrim from year one to year two, because in actuality three years have transpired over the course of the series 51 episodes!

The cabin chairs used in the Spindrift are the same design as those used in the cabin of the spaceship seen in the original "Planet of the Apes" (1968), also in production at 20th Century-Fox in the summer of 1967.

Deanna Lund stated in an interview that if the show had returned for a third season that the producers were going to explore the possibility of a romance between her character Valerie Scott and Mark Wilson, who was played by Don Matheson. This would have reflected the real life romance between the two actors who married after the show's cancellation.