My husband and I booked tickets for a vacation. What happens if I am assur at the time, are we allowed to go?
If possible vacations should be scheduled when a woman is not a nidda. If it was scheduled already and/or there is no other convenient time, they may go when she is a nidda. They must be careful to keep all the harchakos of nidda throughout, specifically while travelling they may not sit on a seat together with which one can feel the other’s movements.
see Igros MOshe Y:D 1:92, 2:83