| Tail Number / N-Number | N421MT |
| Manufacturer | THUNDER BALLOONS LIMITED |
| Model | AX7-77 |
| Year Built | 1979 |
| Manufacturer's Serial Number | 180 |
| Aircraft Type | Balloon |
| Category | Land |
| Builder Certification | Type Certificated |
| Number of Seats | 4 seats |
| Weight Class | CLASS 1 (Up to 12,499 pounds gross take off weight) |
| Engine Manufacturer | NONE |
| Engine Model | NONE |
| Number of Engines | 0 engines |
| Average Cruising Speed | 22 miles per hour |
| Type of Registrant | LLC |
| Owner Name | WIND SURFER BALLOONING LLC |
| Street | 3002 183RD AVE |
| City | CARLISLE |
| State | IA |
| Zip Code | 50047-5456 |
| Region | Central |
| County | Warren County |
| Country | US |
| Fractional Ownership | No |
| Airworthiness Classification | Standard |
| Airworthiness Date | 1979-04-18 |
| Certificate Issue Date | 2020-03-24 |
| Last Action Date | 2022-10-28 |
| Expiration Date | 2030-03-31 |
| Status | Valid Registration |
| Mode S Code | 51200173 |
| Mode S Code Hex | A5007B |