The history of the Kongming Lantern is one that is bewildering to historians here in the West, because in spite of its rather diminutive size, the Kongming Lantern is a product whose background has been muddled by legend, half-truths and historical inconsistencies. Part of the problem stems directly from the Chinese culture itself, whereby traditionally any invention (regardless of the nature of the invention or the field in which it was applicable to) would be accredited to a prominent leader or statesmen rather than the actual inventor of the device. (Whether or not the genuine creators of the inventions were particularly happy with this state of affairs remains to be answered!)
The Kongming Lantern, when originally developed, was intended specifically for military usage, designed as a makeshift aerial spying unit, so as to better keep an eye on the enemy from an aerial vantage point. Whether this was intention ever came to actual fruition remains subject to speculation, and historical records are exceptionally vague and contradictory on this particular matter. A more cynical person would be perhaps inclined to argue that surely these balloons would not be sturdy enough to sufficiently sustain the weight of the soldiers required to properly spy on the enemy.
What we can be certain about however, is that the Kongming Lantern was used as a signalling beacon, in order to provide a critical signal at the appropriate time, and allowed the land based infantry to more effectively communicate with the navy and vice versa. There are countless tales as well of the Kongming Lantern being used as a decoy device, intended to lure unwitting enemy forces to a particular area, only to be subsequently ambushed as they are returned home, tired, weary and utterly demoralised at their futile efforts.