Commuter refers to St Barth Commuter, the only airline with scheduled service between SFG and SBH. Their website is http://www.stbarthcommuter.com/en/

Make sure you're looking at flights between SFG and SBH, not SXM and SBH. SXM flights are a whole different story, and will not work for you on St Barth Commuter. SXM flights work for Winair, but at a different hassle and likely price point.