A transit in the USA is only allowed if you possess an ESTA , a visa or an American passport. You are already checked for these permits when you check in for your flight to the USA, based on your passport number.
ESTA: easier than a visa
An ESTA is easier to apply for than a visa. A visa application requires an appointment at the US embassy. The costs for a visa are also higher. In contrast, the application procedure for an ESTA takes place online, and can be run through quickly and easily. This makes an ESTA the most obvious choice for a transit in the USA.Apply for your transit ESTA now
An ESTA is valid for multiple transfers
The validity of an ESTA is two years unless the passport with which it was applied for expires before that. This makes it possible to use the same ESTA multiple times for a transfer or transit in the USA. You only need to fill in a single date of arrival on the application form. Regardless, it is not necessary and indeed not even possible to provide additional or changed dates of arrival. A new application only needs to be submitted if either the ESTA or the passport to which it is linked expires.
Many travellers journeying from Europe to the American continent make a transfer in the USA
A transfer ESTA is also valid for other travel purposes
In the application form, you are asked if you are only travelling to the USA for a transfer. If you answer "Yes", you do not need to fill in the details of an accommodation in the USA. However, if approved, you will still receive the exact same travel authorisation as if you filled in that you are in fact staying in the USA. This means that even with an ESTA that was specifically applied for to make a transfer, you can still stay in the United States of America for 90 consecutive days for a holiday or business trip. Each trip does need to meet the requirements set to usage of an ESTA.
Can I leave the airport during my transfer?
Based on the above, it can be concluded that you are allowed leave the airport during a transfer in the USA. The ESTA is after all valid for a stay of up to 90 days. However, keep in mind that your airline and the airport where you will be making the transfer can set additional limitations. If you want to be absolutely sure you can leave the airport during your transfer, you are advised to check this with the airline.
An ESTA is also required for transit
Sometimes, confusion arises between the terms transfer and transit. A transfer refers to a passenger switching planes at the airport to continue their trip. During a transit, you land in the USA and wait inside or outside the aeroplane before proceeding to your final destination in the same plane. An ESTA, visa or American passport is required for a transfer and a transit.