MegaMekLab is a BattleTech unit modification program. It allows creating and modifying all unit types available in MegaMek from Support Vehicles up to WarShips. It also allows printing record sheets for single or multiple units.
Seems to be solved by saving and reloading the unit, which tells me this is likely the same issue as #1320 but for Aerofighters rather than Fixed-Wing Supports
Custom Aerospace unit doesn't print SI or external stores show on the Record sheet.
MML Standalone 0.49.17 (but issues goes back to 0.48.0)
BLK File Test Aero Aero.zip
Sample Record Sheet Test Aero Aero.pdf