ISIS claimed to have shot down a coalition jet in northern Iraq today. They also claimed that they captured the pilot of said jet. So far it's just rumors swirling around the internet and twitter accounts of ISIS fighters and fanboys.
Last week a coalition jet belonging to the Jordanian Air Force crashed near Raqqa, Syria which is the defacto capitol of ISIS make believe Caliphate. The terrorist group claimed to have shot the jet down using a MANPAD but they supplied no evidence and it was refuted by Jordanian and U.S. militaries.
The idea that ISIS possesses MANPADS is not far fetched. These weapons are in the hands of Syrian rebel groups and were also seized by ISIS during raids on Iraqi military installations. The most efficient use is against the Syrian army helicopters and certainly not against modern coalition jets that fly at too high of an altitude as well as deploying systems to avoid being hit by a low grade MANPAD