COVID has not been cheap either - it has cost hundreds of billions [0]. You could fund twenty crossrails for this amount of money.
[0]: https://www.theguardian.com/business/2021/mar/22/a-year-of-c...
[0]: https://www.theguardian.com/business/2021/mar/22/a-year-of-c...
(Not just flights - everything except essential goods including via trains, ships and lorries. Certainly all people should have been disallowed entry.)