Many types of visitors do not need an ETA when traveling to the US. Specifically the Visa Waiver Program (covers ~50 countries) does not require travel plans n

Many types of visitors do not need an ETA when traveling to the US. Specifically the Visa Waiver Program (covers ~50 countries) does not require travel plans nor do most visits from Canadians. This is different because it applies to all visitors. I am under the impression some types of Visas allow reentry without declaring ETA ahead of times, but I am unsure.