MAD-BCN air shuttle
 

Does this use the same security lines in MAD as other flights, or does it have its own entrance?

just trying to decide how much time I need to be at the airport before the flight.

upon arrival in BCN, do I have to declare security again for an onward INT’L flight, or will I be able to simply transfer?

thank you.

In theory it has its own security line, but there's really nothing preventing anyone else from using it. I don't know if it's open again, but it was basically a fast-track for people who knew about it and didn't have regular fast track.

Either way, security lines in MAD are rarely more than 10 minutes even at main security. Doesn't seem to be being plagued by the other issues at European airports, but the Puente Aéreo security is to the left of main security and over a little bridge.

Puente Aereo at MAD has its own security. It is a bit hard to find, I suspect precisely because anybody can use it if they want. There is rarely a long queue. As always, it's a question of safety margin + lounge time versus just arriving as late as possible. The gates to BCN are usually in the middle of T4, so not a long walk (assuming you figure out how to get down to the departure level without going all of the way to the trains for T4S)

At BCN, you do NOT need to repeat security, however the arrival / departure gates for the Madrid flights are way down at A1 / A2. It will be a long walk to the central part of the terminal, through the shopping area and up the escalators to passport control (near McDonalds). This assumes that you have your onward boarding pass already, as you are very unlikely to find somebody airside to check you in...

Whatever you do, do NOT blindly follow the people deplaning from the MAD-BCN flight. Many will take the Puente Aereo exit to go directly landside.