Construction inside Schiphol terminal?

I was worried about the same thing, but I'm happy to report that I had a trouble-free transfer in AMS in May 2018. I flew from Entebbe to Amsterdam and transferred to a Delta flight to Atlanta. My KLM/Delta boarding pass showed "Gate A (or Gate 1 - can't remember) anyway, that "gate" was actually a security/passport check. A most pleasant woman in uniform greeted me, asked for my passport, and chatted me up. I didn't realize until well into the conversation that she was doing a deep and very thorough verification of my identity and reasons for travel. Upon reflection, I was most impressed. In any case, it was swift. They had many stations set up to question travelers. Once through the checkpoint, I had access to the entire concourse. You shouldn't have any problems.

There is a world of difference between transferring at Schipol and originating a flight there, as the OP is asking about. Last time I did it was Feb 2017 and it was uneventful then. Don't know if anything has changed since.

Hello!
Now you can hand over your luggage to special vending machines by yourself and register for a flight in the terminal. But the passage of security still takes a long time

There's a number of factors that'll impact security wait times. My personal experience is that last year it took about an hour and a half to get through security and border formalities, while this year security and border formalities was a grand total of 5 minutes.

This link reports how busy Schiphol is expected to be -- https://www.schiphol.nl/en/my-travel-day/09092018

And the Schiphol app has a feature that reports in real time security wait times.

We were in AMS in April. We did not observe any construction.
They advised a 3 hour airport arrival for departing flights.
It took about 2 hours on a Tuesday.
Many flights leave early in the morning.

checking the bags is not the issue; the security lines are just long.
I would suggest staying at one of the hotels within walking distance of the airport.
We stayed at the Sheraton, left the hotel and were in line 10 minutes later.
I would not try to cut this one close

@Marti "I didn't realize until well into the conversation that she was doing a deep and very thorough verification of my identity and reasons for travel."

Oh gosh, I just laughed out loud, literally. Yes, that's me as well. Always thrilled when a stranger asks me about my vacation and boy oh boy am I willing to talk. Then you realize they are just so adept at doing their jobs....yikes. Well, probably something for them to laugh about in the break room! I've even given restaurant and shopping recommendations before I realized they really were screening me. I have traveled enough I should catch on but...no....I'm the Naive Traveler From Idaho.

Sorry, no advice for Continental!

So it sounds like there is order as there was not in on our last trip from AMS. Thank you.

In case I'm not able to check in online, is it still possible to check in via the KLM kiosks and then is there a drop off area for checked bags?

Thanks so much.

Popped through the arrivals hall at Schipol just last week. Took about 45 minutes. The hall gets full quickly, so they stop people at the top of the steps, and before you know it there are 500 people backing up in the terminal. Good news was I walked up to the luggage carousel just as my bag popped out.

Five Schipol runs this year for me....entrance time ranged from 15-60 minutes. Not great, but not awful either. Usually arrive Sunday early morning.

Didn't see a whole lot of construction going on...it's just a busy airport.

Popped through the arrivals hall at Schipol just last week. Took about
45 minutes. The hall gets full quickly, so they stop people at the top
of the steps, and before you know it there are 500 people backing up
in the terminal. Good news was I walked up to the luggage carousel
just as my bag popped out.

Jack, what time of day were you in the arrivals hall?