You're not wrong...
I posted a link to the French Transavia flights previously in this thread. The only airports that have a direct flight to Santorini are: Paris, Lyon & Nantes.
Lalande is situated right inbetween all three airports, although it is a shorter distance to Paris and Lyon.
So, my theory is, they drove all night to Paris, either spent the night at the airport, or a fancy hotel and took the morning flight to Santorini.
Which would match up with the lighting of the vlog and the Instagram picture...
Edit: Further research... maybe they took a Sunday flight from Lyon at 5AM-ish...
All Paris flights leave at the earliest around 8AM.
That would leave them driving from Lalande around 11PM arriving at Lyon airport 2 or 3AM, then flying at 5AM...
From € 54 to Santorini (transavia.com)