Pilot reported losing the alternator on a ferry flight and landing NORDO.

Narrative

I was ferrying Aircraft X from State 1 to State 2; I filed an international flight plan with Canada and I departed ZZZZ / terminal control south bound for customs at ZZZ. Some where 1 hour to 1.5 hour out of ZZZ my alternator stopped charging and my battery died. I put 7600 into the transponder so ZZZ could see me coming in on radar. 20 minutes out of ZZZ I started calling the Tower on my cell phone. I called around 15 times and failed to get Tower on the phone I left a voicemail letting them know I lost my comms and I needed to land for customs. When I didn't get through and no one called me back I proceeded into Class D airspace and looked for traffic and kept scanning the area like you would in uncontrolled environment; I landed and got off runway as fast as possible; I proceeded to taxi to customs. I couldn't see any lights from Tower during flight or taxi.Once at customs I was told ZZZ Tower claimed I had no flight plan; I called verified I did with Canada; minutes later ZZZ did acknowledge I had a flight plan. Spent 2 days in ZZZ getting aircraft repaired for continued ferry flight. Left when aircraft comms was repaired with no issues.