I’ll give you jeans – they particularly are in contradiction of znius standards – and may even admit that a pantsuit should not be part of “bas Ysroel” clothing. I am less sure of ski pants (when skiing)or culottes or pants worn UNDER A SKIRT. BTW- on a summer day , it seems to me to be a lot more comfortable to wear skirts.
But our discussion has more relevant issues like – halocho lemaase- a family goes on a long car trip of say, eight to ten hours. Only the family members are present.It is a lot easier for a woman to travel in a pair of comfortable pants (to get in and out of the car, for example.)What if she asks to wear a comfortable pair of sweatpants? No major issue of znius- the pants are made for a woman, they are not tight and only her husband is present anyway.
If the issue is not one of “lo silbash”, then it should be permissible,as there aren’t any znius questions. If there is a problem of ‘lo silbash”, then it changes the whole question. Nu,how would you pasken?