Final answer:
The character Gabe likely experienced surprise or misinterpretation when he thought he saw a plane. The exact nature of this observation is unclear without further context from the text where Gabe is a character.
Step-by-step explanation:
When Gabe thought he saw a plane, it's likely that he was witnessing something unexpected or out of the ordinary, which led to surprise or confusion. The context from which this question is drawn suggests the figures Gabe saw were mistaken for planes due to their appearance against the sky, or because of their movement. Since the excerpts provided do not directly reference a character named Gabe, the precise answer requires additional context from the specific text in which Gabe appears. However, it is common in literature for characters to misinterpret visual or auditory stimuli, leading to plot developments or changes in perspective.