Answer:
Margo feels nervous and guilt for throwing the paper airplane and is afraid of the consequences that may follow, while Alan feels excitement since, "someone besides him had done something foolish."
Step-by-step explanation:
As the words in the text can be utilized to infer, Margo was nervous, and the guilt is brought in by the words, "She wanted to... apologize.." Alan is excited since he's the only class clown, and as I've quoted already for him in the answer, he's normally the only one to do foolish things like throw airplanes.