Wakes at mesothermal conditions are studied in a plasma wind tunnel which simulates ionospheric flight conditions. The need for a very low pressure in the chamber, provided by a liquid-helium trap, is shown. Wakes of bodies large with respect to the Debye length are investigated and the ratio Te/Ti (electron temperature/ion temperature) can be varied. For Te/Ti≫1, an ion density peak arises in the midwake and ion waves propagate in the far wake. For Te/Ti≈1, peaks and waves are entirely suppressed. A quantitative agreement with different theories is achieved.