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We bought a van in Canada to roadtrip the US for 6 months. We are planning on two 90 day stints in the US so as to comply with the ESTA requirements. It is looking more likely it will be easier to fly Mexico rather than re-enter Canada via land. Will customs have an issue with us leaving and re-entering the US via air if we originally entered via land border? We have done the west coast and want to now travel the East coast. Thanks.