The civilian spaceport (with military involvement) developed by millionaire industrial genius Greg Masterson is called Earthport 1.

Straker's remark to Foster about civilians taking Skylark trips into space probably references the British Skylark sounding rocket, a rocket normally used to take various types of instrument readings during a sub-orbital flight. Since the rocket was only capable of sub-orbital flights (and was fairly small), it seems unlikely it would be useful for travelling to Earthport 1.

The general Straker deals with in this story is said to be his usual nemesis, General Henderson, on page 4 of the story, but it doesn't look much like the actor who portrayed him on the TV show. On the final page, Straker refers to the general as "Craddock" instead, so I assume the first reference was a mistake by the writer or editor.

One of the Interceptor pilots on page 2 of the story is called Bill. Possibly this is Bill Johnson, a pilot who appeared in "Identified" and "Computer Affair".

On page 5 of the story, the aliens are able to gain telepathic control of the human truck driver. How they do it is not explained. In some past stories, the aliens have needed devices or hypnotic programming to take control of humans telepathically.

A SHADO operative named Matthews is assigned by Straker to watch the spaceport that is scheduled to launch supplies to Earthport 1. Possibly, this is meant to be Ken Matthews, later seen as an Interceptor pilot who is killed in a collision with a UFO in "Computer Affair".

The ship one of the aliens steals away on to Earthport 1 looks like a SHADO Lunar Module, but it launches from the spaceport on Earth like a standard rocket instead of from a sub-orbital vehicle as seen in the TV series. 

UNANSWERED QUESTIONS

Is the General Craddock of this story the same one who was in command of an arctic base brought under SHADO control at the end of "Arctic Affair"? The man looks more like General Calper, who temporarily replaced General Henderson as head of the I.A.C. in "The New Boss" and who had a similar anti-SHADO attitude. Frankly, I prefer to think that the names of Henderson and Craddock used here were both in error and it is actually Calper depicted, as it lends a greater continuity between stories.