I always travel with my VAX card even though I know it is highly likely I may not need it.
Why? The Government can (and will) impose anything at anytime, and I would hate to travel anywhere and get stuck there because of a sudden VAX proof requirement to fly home.
Another nice thing to having the VAX card with you? If you are out of state and suddenly want (or need) a booster.......
NOTE: The Government is currently forecasting a summer time surge in Covid. Let's hope it doesn't occur but past history shows otherwise.
Enjoy your summer trip to Hawaii.
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