I've always found that by the time you've factored in travel time to the airport, checking in, then clearing security, boarding, actual flying, then waiting for the bags at the other end that flying takes the same sort of time as the train to somewhere like Lyon or even Valence, especially if you go to Lille and avoid the transfer across Paris. It's even quicker now the high speed link to the tunnel is operational.
I've always found that by the time you've factored in travel time to the airport, checking in, then clearing security, boarding, actual flying, then waiting for the bags at the other end that flying takes the same sort of time as the train to somewhere like Lyon or even Valence, especially if you go to Lille and avoid the transfer across Paris. It's even quicker now the high speed link to the tunnel is operational.