One of the first things a young person should learn and become proficient at before embarking on the road to adulthood is plane etiquette. There are three main guidelines that one should always abide by. Window etiquette comes first, followed by aisle etiquette, and finally—possibly the most crucial—baby/parent etiquette. The original poster (OP) is traveling with her 19-month-old son on a three-hour flight. As instructed by the airline, she only purchased one seat, hoping the baby would drift…