Airports in Madrid and Lisbon

It all depends on which airline you are flying on and also whether you are flying schedule or charter.

It's the airline not the airport that sets the rules regarding boarding time.

I'm referring to the time aspect of just getting thru all those "security" lines. Here in the states, one airport can be vastly different from another in how many "cattle lines" there are usually open, etc. I'm flying both Vueling and Easyjet on regular flights.

You won't need 3-4 hours to get thru Barajas in Madrid. Easyjet flies out of terminal 1, with their checkin desk opening 2 1/2 hours before flight time...the earlier you're in line, the better choice of seat. The access thru security is at the far end of the terminal, but they've been pretty good bringing more people in when lines get long. Vueling flies out of the new Terminal 4, which has more security stations available. But it is a looooong walk to the Vueling gates from the central security area.

The actual "boarding process" on board the Aircraft usually moves along rather quickly.
I take it you are asking about the process of check-in, screening, travel time to the gate etc?

It really depends on the distance to the gate. If the Aircraft is parked at a far away gate, it will take longer to walk etc...
And in some cases, like LIS, you may have to board a bus and shuttle out to the Aircraft. But that's usually about a five minute ride once boarded.

I know it will not take 3-4 hours in LIS. It has never taken that long anytime we've operated flights from there over the years going there 3 times a month every month during high season.

I think LIS is pretty efficient. Or at least more so than say ten years ago when I first started enjoying layovers there...

I went through Lisbon airport in December (flying KLM to Amsterdam), albeit at 6 am, but security and everything was a breeze.