So what if the Hungarian army decisively defeats Jelačić at either Schwechat or even earlier, not allowing him to retreat and join up with the rest of the Imperial forces.
Vienna is in open rebellion, could the arrival of the Hungarian army topple the Habsburgs for good?
At this early stage of the revolution there was no plan of outright secession, so perhaps we could see an earlier, and very different Austria-Hungary? Perhaps with a contitutional monarchy, with a Habsburg still on both thrones, but rather powerless?
Or would the Austrians fight on from Tirol and Prague? What if the revolution spreads to the rest of the empire? How do the other great powers react? IOTL Russia entered the conflict on the Austrian side, but with such rapid revolutionary success, could they react in time or would the Habsburgs try to negotiate in order to stay in power?