Well the 10 month is golden you can fly for free until they are two years old. The three year old is going to cost you full fair. Mine is turning two in sept. and im going to realllly miss that lap child free thing. they charge full price regardless of the age because they are occupying a seat. Enjoy the lap child for free while you can. I can imagine paying for two kids would start to get a bit pricy. Good Luck!!