Balloons were used for recon in the Civil War, made effective by running a telegraph line from the balloon to the ground. However, because they remained tethered, the info was of necessity narrowly collected of a selected battlefield before and during the engagement. But it was still a significant asset, because they were able to not just provide battlefield intel to commanders, but also acted as floating aerial forward observers for the arty, enabling them to hit unseen targets with accuracy. Yet they were not willing risked floating free over the enemy - I know of at least one occasion where a recon balloon was shot down because it broke its tether to keep it out of the hands of the enemy.

There's even a claim for a first aircraft carrier - there was a recon balloon run up off a purpose-built barge in the first year of the Civil War which addressed part of the fixed position problem by being able to tow a balloon up or down river while it was tethered to its deck.....