Hi Eva- Please try something for me: try to get along with your ex. The more reasonable & kind you will be the more you'll get kindness & cooperation back. He may be a jerk... but just try. When dealing with my ex, the first thing I ask myself: will this (question/ action) harm or benefit my child(ren)? Its really hard, I know, but we married (or at the least made a child with) this man--we need to be able to get along. Good luck!!! =)
I don't know about the laws where you live...but in some countries/states/provinces if you have split custody he would have to tell you legally if you asked because you make the decisions together...but most airlines will not let a child board or cross a border without a legal note from the other parent as well as the birth certificate and passport (depending on the age). If he just took your child on a trip and is back home...just remember as mad as you may be your child deserves that trip and quality time with daddy as hard as it may be for you...of he took off with your child and you fear you will never see the child again..call the police and they can put out an alert to stop him from boarding and planes.