Wonder is the first time. The log is every time after that.
Plane spotting has always come with a notebook. The hobby was built on them: a date, a registration, a type, sometimes the weather. The notebook was the point. Without it you had an afternoon; with it you had a collection that grew for years.
The instinct behind that is worth understanding, because it explains why a log changes the hobby rather than just recording it. Watching one aircraft is a small pleasure that ends when the aircraft does. Writing it down turns it into something cumulative. The second time you catch the same registration, months apart and in a different city, it is no longer a coincidence. It is a thing that happened to you, and you have the proof.
A log also answers the question that follows every good sighting. You saw something unusual. Was it? Compared to what? A notebook full of the ordinary is what makes the extraordinary legible. You cannot know a catch was rare unless you know what common looks like, and the only way to know that is to have written the common down.
The modern version does not need to be a notebook. Your phone already knows where you are, which way you are pointing, and what is overhead. It can do the writing.
Plane and Simple records a sighting the moment you tap an aircraft. You do not fill anything in.
Each entry keeps the call sign that identifies the flight, the aircraft type where the databases can resolve it, the airline, and the country the tail is registered in. It also records the state the aircraft was in when you caught it: its altitude, its speed, and how high above the horizon it sat when you looked up.
And it records where you were standing. That turns out to matter more than it sounds. A logbook of aircraft is a list; a logbook of aircraft and places is a record of your own movements, seen from underneath. The flight you caught from a hotel balcony in a city you visited once is a different memory to the one you caught from your own garden, and the log knows the difference.
Where a photograph of the airframe exists, the entry carries that too, so the collection is something you can look at rather than only read.
This is the distinction most spotting apps get wrong, and it is the one that decides whether a log is worth keeping.
Every aircraft broadcasts a unique 24-bit address, its ICAO24, which belongs to the physical airframe and not to the flight it happens to be operating today. A call sign changes every day; the airframe does not. Plane and Simple logs against the airframe, which means your collection counts aeroplanes, not journeys.
The practical effect: catching the same 737 on Monday and Thursday does not inflate your collection to two aircraft. It does something better. The app recognises that you have met this one before and tells you so, which is how a collection acquires the quality that makes collections worth having: the ability to be surprised by a repeat.
It is also what makes counting honest. A log that counted flights would reward you for standing under a busy approach path. A log that counts airframes rewards you for looking up in more places, over a longer period, at more of the sky.
A month in, the log stops being a list and starts being a shape.
It knows how many distinct airframes you have caught, how many types, how many airlines, and how many countries of registration. Those four numbers move at very different speeds, and watching which one is stuck is how you work out what to do next. Plenty of airframes but few types means you are standing under the same short-haul traffic every day. Plenty of types but few countries means you have never spotted anywhere but home.
There are nineteen achievements built on those questions, three of them hidden. The straightforward ones mark progress: fifty airframes, twenty-five types, ten countries of registration. The better ones cannot be pursued at all: catching the same aircraft on two different days, catching the same route flown in both directions, catching one directly overhead, catching one in the small hours.
They are computed from the log rather than counted alongside it, which has a useful consequence: an achievement added in a later release still awards against sightings you recorded months earlier. Nothing you have already caught is ever wasted.
A log is only worth keeping if it outlives the phone it was kept on.
Your logbook syncs to your own iCloud account. Not to a server we run, not to an account you have to create, and not to anything we can read. A new phone restores the collection; a lost phone does not cost you it.
There is no sign-up, no profile, and no leaderboard. The collection is yours, and the only person it is trying to impress is you.
The app is free. All of it. No subscription, no premium tier, and nothing about the logbook is held back.
See what's flying above you. In augmented reality. For free.
