Just finished watching the episode again and there were some things that occurred to me.
Diane's anxious glancing at her phone (which just displays a screen saying BLOCKED) on the plane. Is she expecting the text from Mr C, or simply doesn't like being offline for a while?
Ike's squeaky "Oh" or whatever sound it was when he's caught made me laugh.
I noticed the reversed number on the plane too this time but I wonder if that was more to do with filmmaking techniques. They appeared to be flying from right to left when they were heading to South Dakota, so now when they're heading back the other way they may have reversed the flight footage to emphasise that this was the return journey.
On the bad drugs subject:
In Ep3 Truman says there's been another apparent OD, little Danny Craig, probably Chinese designer drugs
Bobby says they're not coming down from Canada
In Ep6 Red says they're moving the 'sparkle' down from Canada
The woman living opposite the house where Dougie and Jade meet appears to be on them
Ella (woman at the end of this episode) appears to be suffering some effects of a bad batch
I have no idea how any of this relates to anything else though.