Software engineer, electronics hobbyist.
I agree with the Arduino approach for learning: try something that immediately gives feedback.
On a more concrete example you can start with Make: Electronics book by Charles Platt. PDF of the first edition (2009) is available from Makezine’s own CDN. The book encourages learning by discovery. The leading text makes it clear:
Burn things out, mess things up—that’s how you learn.
Do flights normally provide free drinking water? I am under the impression that passengers must buy bottled water in flight if they want to drink.