The most accessible thing comes from the August 24, 1967, rebroadcast of "Space Seed". Rather surprising sponsors for a youth-oriented show, especially Geritol, the regular sponsor of Lawrence Welk.

Star Trek had to get whatever ads it could, regardless of its audience demographics, because it had problems with consistent sponsorship throughout its run.

Going through the trades reveals several types of sponsorship:

• Sustaining: The network or station pays for the program without a commercial sponsor. PSAs would fall into this category.
• Single sponsor: One advertiser finances or sponsors the program.
• Participating: Multiple advertisers buy commercial time within the same program.
• Alternate sponsor: Two or more advertisers take turns sponsoring a program, often on alternating weeks.
• Cooperative local sponsorship: Local sponsorship in which costs or advertising support may be shared, often between a manufacturer and local dealer or retailer.

So, for instance, Bonanza had Chevrolet locked-in as a long-term "single sponsor," with the tradeoff being NBC got less revenue per minute of advertising, but stable, predictable ad revenue.

Star Trek, OTOH, never landed a single sponsor, and it appears that ads were sold on a "participating" basis only. This meant sponsors came and went. Brown & Williamson Tobacco Corporation is reported as a participating sponsor for the show in winter 1967, which is why you've got those Viceroy ciggy ads in that "Space Seed" rerun. I have some reporting on which agencies were buying "participating" ad spots, but that information doesn't usually include specific brands repped by those agencies. It's something we'd like to know.

Herb Solow addressed the sponsorship problem in Inside Star Trek, e.g.:

• "NBC sales had told me our show wasn’t “sold out”—that portions of the show still lacked sponsorship"— p253
• [QUOTING Weekly & Daily Variety reviews] "And there was even more that NBC Sales and any of the participating prime-time Star Trek sponsors certainly did not want to read"—p265
• "NBC, suffering financial losses on Star Trek due to lack of sponsorship, refused to pay any additional monies"—p324