Specifically, the fact that the original two Supervisors were killed in a car accident. What the hell were they doing in a car in the first place? They don't need cars, they have the magic transporter vault that we saw Gary Seven use. Did any novel ever try to explain this?
Yes. I believe it was in one of Dayton Ward's historical books. I'm pretty sure it was "From History's Shadow."
I always assumed that they were trailing someone who was driving another car, since “Assignment: Earth” was suppose to be a spy series and they couldn’t use the transporter.
Honestly, I don't see a problem here. Any agent who is living undercover in 1960s America, and trying to blend in, is going to end up driving around sometimes, if only to protect their cover as an ordinary American. The transporter would be handy on vital missions, when you suddenly need to be in Moscow or Cape Canaveral in hurry, but I doubt they used it to go to the grocery store or pizza parlor. Indeed, using the transporter just to get around would risk plenty of awkward questions: "Thanks for coming over, Bill. Um, I don't see your car. Where are you parked?" For all we know, they were killed driving home from a friend's birthday party. Or were catching a ride with someone else.
Yeah, it's From History's Shadow. I hadn't heard about that, so I was really surprised when I hit that part of the book and realized what was going on.
https://memory-beta.fandom.com/wiki/Elizabeth_Anderson https://memory-alpha.fandom.com/wiki/Agent_201 https://memory-beta.fandom.com/wiki/Ryan_Vitali https://memory-alpha.fandom.com/wiki/Agent_347