Working from the numbers quoted  here and some random graphs of thrust it looks like most of the thrust around max Q is going into drag (~40 thousand pounds), which sorta makes sense since if it wasn't things would accelerate further and it would not be max Q.

Do have a think about how your sideways Saturn V is being supported during the air lifted part of things and how much weight that adds, and have a look at The air launch tag

and an existing air launch system

There are advantages in air launch but raw vehicle cost is not likely to be one of them.

Edit: original version of this answer was wrong at least three different ways. Answer quoted here gives drag as around 460 thousand pounds. With a total upper stage weight around 262 thousand pounds and 2Gs acceleration at that point suggests the second stage loads from the upper stages are very approximately 50/50 between the two load sources, assuming most drag is on third and higher stages or the fairing at the top of that stage. More reading suggests fins on first stage added a fair bit of stabilising drag so this is wrong but hopefully not as wrong as my first answer.

Not part of your question but The air launch tag and

and an existing air launch system may help frame more questions.