Okay, depending on the school:
Any absence, is an absence. Therefore, at the end of the quarter or semester, when absences or tardiness is accounted for for each student and a report comes out, per the Dept. of Education or school, a child will have all the days he/she missed, as an absence.
Whether the child is sick with a Doctor's note or on a trip, does not matter, It is an absence. It is NOT an excused, absence.
That is how it in our State is per public school.
And yes, there is a certain amount of absences, that is allowed, for a school year.
My son for example, missed about 10 school days. He was, sick. Literally. We went to the Doctor. I had Doctor's notes each, time. It is STILL an unexcused absence and it is still, counted as an absence. And for example, IF he was not doing well in school and was below par etc., he "could" be held back. Due to excessive absences.
An absence is an absence.
How old is your child?
Sure, traveling is always educational. And a good experience. No matter what age. When I was in elementary, my parents took us on so many trips. All around the world. I saw more places than some adults see in a lifetime. But some occurred when I was too young, to even remember it now.
If you plan a trip, that is NOT during a school's scheduled holidays or breaks, then your child will be marked as absent for those days. And, typically a parent will tell the Teacher, AHEAD of time of a trip, so that the Teacher then has time.... to compile together that student's in-class work and homework and/or projects/assignments, that that student will be missing, while gone.
I have heard some kids/Moms say "why should my child have to make up work once he returns to school? We were on a trip, why go on a trip if he will have homework?" Um well, all the students in that class, have those assignments and school work to do and they are being graded on it etc. A trip, does not excuse a student, from doing the school work.
Just as when a child is out sick, when they return, they also have to make up the work and catch up.
It is harder in older grades. ie: from like from 3rd 0r 4th grade onward. Because, they have more work and/or homework to catch up on.
At any given time, there are always kids who are not in school, because they are on some kind of trip for whatever reason. For some reason, not all families can or choose to, plan trips during school breaks or holidays.
Most Teachers I know, especially in the older grades, do not jump up for joy, when a student is gone on a trip during regular school session.