I've seen hundreds of Kirby originals online from the late 1960s with Kirby margin notes, but I'm no handwriting expert so not 100% sure these are Kirby notes because they are so small; at an angle; and the style seems to shift between cursive and all-caps (Jack's later margin notes are bigger, in all capital letters and written horizontally).
These might be early examples of Kirby margin notes, written hastily to give Lee some additional ideas and clarify Jack's plot, but as I look at them closely, I wonder if they were written by Stan Lee -- possibly when Jack first presented him with the art: Stan added notes to himself, or as he looked at Jack's original artwork for the first time, he made some quick annotations for future reference.
Let's go ahead and zoom into the artwork. Panel 1: a great example of early FF. By now, Jack had really established the look of the characters. Notice how you can still see Jack's pencils for the Human Torch underneath Dick Ayers's inks.
Maybe it was a cold winter day in NYC so the torch has his flame on, trying to keep his friends warm.
Panel 2. The Thing looks hilarious in his own little piece of the flying fantasti-car. The torch is still on fire even in the vehicle -- guess the machine is flame-proof.
Nice work by both Jack and Dick giving you a modern New York skyline with an economy of linework. I love the shape of the building in the middle -- it looks like an orange juice container.
Panel 3. The Thing lands in a parking lot, and gets yelled at. I'll try and translate the tiny margin notes on the left side of the page. I think they say:
(1) "No airplanes!" (2) "Not plane" (3) "Car with wings."
Notice if you zoom into the Thing's body, you can see dark, solid pencil-shading representing his rocky body, but Dick Ayers chooses to use parallel lines instead. We can see that Jack's version of the Thing was more blocky and sharp-edged as opposed to the softer, rounder look Ayers gave the character.
Panel 5. Not sure what those margin notes say. I have no idea what that third word is.
"I can't (?) you." Maybe "I can't lose you."
Panel 6 and 7. Nice melodramatic spotlight on both characters in the first panel.
Let's zoom into the margin notes.
My translation: "But if anything happens to you I'll be alone -- nobody to protect me."
A closer look at the last panel. Beautiful delineation by Ayers here.
Notice the subtlety of Ayers's inking on the eyes, and Jack's pencils beneath the inks. It's too bad Marvel doesn't reprint material like this, shot from the original artwork -- you really can see the symbiosis of penciler and inker at work here.
Thanks to Kirby Biographer Mark Evanier for answering my question: Were the margin notes on this page written by Kirby? Here is Mark's response: No, they're Stan Lee notes to someone else in the office...probably Sol Brodsky.