In the War of Wrath, when the Valar, Elves and Men fought against Morgoth and his assembled forces
There Melkor releases his last and greatest force, the fleet of winged dragons, that had never been seen before
To my knowledge, the Fall of Gondolin happened before the War of Wrath, and yet in the Fall of Gondolin, dragons attack the city (apparently with Balrogs riding on them).
Were the dragons at the Fall of Gondolin wingless?
Yes; the dragons that attacked Gondolin were of the wingless variety, the spawn of Glaurung, the first dragon. From The Silmarillion:
and he loosed upon Gondolin his Balrogs, and his Orcs, and his wolves; and with them came dragons of the brood of Glaurung, and they were become now many and terrible.
...and there was no stay in the advance of the foe until they were beneath the very walls of Gondolin, and the city was beleaguered without hope.
If these dragons were capable of flight, the walls would have been irrelevent, and the city would not have been beleaguered but overrun.
The oldest form of the story the Fall of Gondolin was written in 1917, just a year after Tolkien had personally seen the first uses of tanks at the Battle of the Somme; the dragons in that story have always represented tanks, and were thus of the wingless variety.
