Trading standards is investigating a leaflet from a firm purporting to support the air ambulance.
Derbyshire officers are investigating complaints the unnamed company has been misleading people into thinking they were supporting the air ambulance in this and many other areas.
It does not have any connection to Derbyshire, Leicestershire & Rutland Air Ambulance, or the Warwickshire and Northamptonshire Air Ambulance.
An air ambulance spokesman said: "Any donations made to this company will not go towards your local air ambulance service.
"The leaflet is very misleading and could easily lead people into thinking they are supporting our vital life saving service.
"As a registered charity we rely on voluntary income to keep us flying and saving lives and it is upsetting that this company seems to be confusing people. I would urge supporters to look for our registered charity number (1098874) when making a donation or call the team on 08454 130999."