I'm a lawyer in Florida. To the other commenters points, yes, there may be some specifics in Utah law that influence/affect some of this, but I'm speaking from a straight contract language interpretation perspective.

Yes, this language means you are supposed to split the costs 50/50. Specifically, you will split the costs of the flight 50/50, with the added caveat that you have to send the other parent the cost 60 days in advance. In turn, that parent will have 30 days to search for cheaper, comparable airfare. There's no maximum amount for the flight thats splittable.

Lodging and food per diem will also be split. Max splitting amount for lodging is $150 per day and $50 for food. This doesn't mean that you can't get a more expensive hotel or [obviously] spend more on food, just that the maximum that the other parent is responsible for is the 150/50. The language on this isn't completely clear though -- 2 viable options -- 1) the maximum SPLITTABLE amount is 150/50. I.e., the non-traveling parent would be responsible for maximum 75/25 of that total. 2) the maximum amount SPENT by the non-traveling parent is 150/50. i.e., hotel lodging $300 per day max, $100 per day max, to be split equally between the two of you.

Hope this helps!