| Business | Phone |
| Aerotronic Services 7940 Airpark Rd # R, Gaithersburg 20879 | (301) 948-2510 |
| American General Supplies Inc 7840 Airpark Rd, Gaithersburg 20879 | (301) 590-9200 |
| Delta Aviation Inc 18974 Bonanza Way, Gaithersburg 20879 | (301) 216-9714 |
| Hari Group Inc 7844 Beechcraft Ave, Gaithersburg 20879 | (301) 216-9881 |