No, thermal cameras cannot see through cars. Thermal cameras detect infrared radiation and are used to measure the temperature of an object. Since car windows absorb most of the infrared radiation and reflect very little back, they appear as dark objects in a thermal image. In other words, while thermography can be used to detect heat signatures coming from inside a vehicle, it won't be able to show any details about what is going on inside since the windows block out the majority of infrared light.