My AirPods disconnect while playing music from Apple Music on iPhone 6s. Well, one does, never both at the same time. Sometimes the left AirPod, sometimes the right. Sometimes the AirPods are error free for a week. Sometimes I will loose connection two times per day or more for several days in a row.
If you do not have the case with you, no amount of fiddling will fix things. The only fix is to place both AirPods back in the case after stopping the music. Then taking the offending AirPod out first, then the other. Restart the music. Sometimes this works on the first try, sometimes it takes several tries.
When I go for a walk, I like to travel light. Having to always take the somewhat bulky charging case, even for a short one hour walk means one less other thing I can take. For bike ridding, my shorts do not even have pockets and stuff is contained in an armband - no room for the charging case.
I have other Bluetooth headsets, such as the Plantronics Backbeats and in-ear Beats, but they cut out too much ambient noise (traffic, etc.) to be safe while bike riding. The AirPods let just enough of the outside world in - but this issue with disconnecting makes things frustrating, when it should not be.