There are several things you need to do, to cross the U.S. and Mexico border by air.
It may seem overwhelming, but once done, you get used to the process. There is a lot of bureaucracy on both sides of the border that want to document your crossing and no one seems to talk to each other.
U.S. Customs and Border Protection.
DTOPS annual vehicle (aircraft) user fee
eAPIS (Electronic Advance Passenger Information System) (easiest with www.bajabushpilots.com, which includes Mexico APIS)
Airports of Entry where CBP can inspect and record your border crossing.
Passport to identify you upon entering the U.S.
Mexico (at airports of entry)
Immigration (pay for Entry Fee and Tourist Card to keep in Passport)
Customs (inspect aircraft and baggage)
Commandant’s Office (pay for annual multi-entry permit and file flight plans)
US and Mexico ATC
Provides transponder codes and traffic advisories.
In addition to my below information I found this informative description of the border Crossing Process. It’s a bit dated about fees, but otherwise very accurate.
From the USA to Mexico
Before departure:
DTOPS sticker ( https://dtops.cbp.dhs.gov/main/login_internet.jsp )
– Do this as soon as possible. If you do not receive the sticker in time for your trip, bring a receipt of payment with Decal Number shown.
ID Document copies
I scanned all my documents needed to enter the country and gave a copy to the Commandant prepairing my annual multi-entry permit in Mexico. He seemed happy to get my information and got started filling out his papers.
– Pilot page with: my Passport, Pilot Certificate, FAA Medical and Radio Operator’s permit.
– Aircraft page with: my aircraft registration, Airworthiness Certificate and DTOPS receipt.
– A few pages from my aircraft insurance policy, highlighting “territory…Mexico.”
APIS
– Submit manifest with both USA and Mexico. Easiest method to submit both US and Mexico APIS is with Baja Bush Pilots, members get free APIS filing service. (www.bajabushpilots.com)
– You can depart from an airport without immigration services, however APIS will show the nearest international airport as your point of departure.
– Receive email from US Border Patrol advising cleared to depart U.S.
File flight plan with U.S. flight service.
– Call 1-800-WX-BRIEF, file for leaving and preferably returning to the U.S.
– You can call from Mexico to file the return if you have a phone that works.
Call Port of entry to advise of your arrival time.
– Baja Bush Pilots has phone numbers for international airports in Mexico (https://www.bushpilotsinternational.com/page.php?name=mexico#International_Airports)
In the air:
If VFR, squawk 1200 to cross the border.
Call flight service radio to open your US flight plan.
– I called San Diego radio to open my flight plan.
– I then called San Diego approach for flight following.
– Before crossing the border, I canceled flight following and squawked 1200.
Radio to Mexico TCA prior to entry.
– Get squawk code
– I called Mexicali approach, 5 miles north of Calexico.
Once arrived at your port of entry.
Go through Immigration
– You will get a form placed into your passport. Don’t loose it.
– I was free as a pilot, however my passenger was asked to pay a fee.
Get bags checked.
Pay for a Mexico annual multi-entry permit.
Pay for gas.
File a Mexico flight plan for next flight.
From Mexico to the U.S.
Submit APIS manifest with both USA and Mexico.
– Receive email from US Border Patrol advising cleared to depart for the U.S.
Confirm U.S. flight plan has been filed for that day.
File a Mexico flight plan
Check out of the country with immigration.
– They will take form from your passport.
Check out of Mexico with your multiple entry permission form.
Call the U.S. airport of entry border patrol to advise of your arrival time.
Depart to a port of entry in the U.S.
Communicate with Mexico ATC.
Radio flight service to activate flight plan and get squawk code.
Once I received Squawk code from U.S. I informed Mexico ATC, I was switching codes.
Communicate with U.S. ATC
Get checked in by Immigration/Border Patrol