when certain countries are coming back and others aren't and that will fuel demand and supply mismatches -- it's hard to really know. uncer uncertainty, markets sure don't like that. >> putting the science aside, people want to argue over the science as to whether they should get vaccinated, whether we should have vaccine mandates. putting the scientific argument to the side, not to say it's unimportant, but strictly from an economic standpoint, would it make sense for the airlines to adopt vaccine mandates, do you think? >> i think it would. i think that particularly when it comes to business travel, that would make companies feel a lot better, a lot safer. i think we're probably headed that way. you can also already see in certain cities around the country and the world that you do have to show your proof of vaccine. i can tell you, i went to get my booster today. there was a very long line out the pharmacy. i suspect it had something to do with this variant. >> i suspect you're right.