Even with WiFi disabled and airplane mode on, though, the battery still drains in a matter of days, so it certainly isn't the only thing causing the horrendous battery life.

For comparison: two days ago, I charged my six year old Galaxy Tab to 100%. I used it for about twenty minutes, then put it in airplane mode. I just checked the battery again: 96%. The Jolla Tablet in the same scenario would be closer to 46%.