So why did Sen. Barack Obama come to the back of the plane and join reporters on Monday?

Well, it was, in part, to thank NBC embed Mike Memoli for the cookies his mother had sent to Obama.

While home on Sunday, Memoli told his mother -- famous at The Hotline (Memoli's previous employer) for her cookies -- that Monday was Obama's birthday so she sent her son back on the trail with some homemade treats (she once gave Bill Clinton cookies, too).

Memoli gave them to the campaign ("If you can pass them on to him, it would make my mom happy," Memoli told the campaign staffer) and, lo and behold, Obama joined reporters later to thank Memoli for the gift.

Obama's "thank you" trip worked out well for reporters, who used the occasion to pepper Obama with questions.

Memoli is temporarily on the Obama beat, as regular NBC embed Athena Jones is on vacation.