If you mean a bright red spot on the white part of your eye, and no worsening of vision and no pain or just little irritation that is usually a subconjunctival hemorrhage. They are very common and do not represent a contraindication to flying. If you have an Eye MD or optometrist you might call and ask. Artificial tears make them feel better and perhaps go away quicker. The plane air is dry which aggravates the mild irritation some people have.