Hi, I would check the operator of this train. In this case Swiss Federal Railways SBB.ch and local trains company for Lombardy region TRENORD.it . To Malpensa there are some routes, you can travel via Milan using Malpensa Express from Milano Centrale or you travel via Varese wich should be a direct service. 

There is an hourly  train and other than the 0806 they all show as valid. You do not require a reservation for this S-bahn train so just turn up and board - once you have added it to your travel day of course.

I have no idea why the 0806 is showing as an invalid train.

The Malpensa Express from Milan is not valid with passes. It is run by Trenord, all of their other services including other connections from Lugano to Malpensa are valid.

I am seeing hourly connections at xx.06 from Lugano taking 1h35min, either direct or changing in Mendriso.

Please don't use the rail planner app or the Eurail website to plan. They're not reliable, as we see here: the connection leaving at 8:06 with one change is listed in the app as "Not in pass network” but that's nonsense. The pass is valid and it's a direct train, running every hour.

Lugano to Malpensa airport is best done on the direct trains via Mendrisio. The pass is valid.

Not all Trains to Malpensa are valid with a Eurail Pass, this is the case for the Malpensa Express. If it is not valid also for the S trains I don’t know. Best way is to ask directly Trenord. 

The VERY last sector from the last stop to MXP is considered to be all 1st cl and this makes also normal ticketing a nightmare. Has to do with what so very often happens with airport lines: extra high fares. I believe a ticket for that last few KMs is only 3€, have forgotten now what last stop is called. Can see by clicking on train nr of the train used-then you can see all stops.

But in my rather limited exp. going there there has never been any enforced check on this.

F.e. in BRU/BE and for Arlanda/STO=SE one also has to pay extra fees to be able to enter or exit train station there. In ES most metro to airports charge 5€ or more, whereas normal fare is about 2.

I cannot find any reference to any requirement for a supplement for Interrail passengers with a second class pass approaching Milan Malpensa from Switzerland on the S bahn trains.

Are you suggesting that all second class passengers have to disembark at this mysterious station or have 2 tickets?

I do see that the direct Malpensa express into Milan Centre is not available to pass holders with any class pass.

If there is a reference, rather than just your memory, could you please post it for all the community members to refer to when answering these questions.

Like every time mcdv mixed up things.

If you buy a ticket from like Lugano or Milan to the last station before Malpensa Airport is like 10€, if you go to Malpensa you pay 20€ and not first class (first class is the Leonardo Express in Rome).

I think there could be a problem due to this higher ticket price on this last section with the acceptance with Interrail Passes. This could be solved like in Brussel Airport with the Diablo fee, but better to ask full fare for Trenord.

Best here is to ask directly Trenord. But they are not known to know very well their own rules....