Nikon L840 For Plane Spotting?

And also for landscape pics?
And your overall thoughts of the L840

It's a fine camera for what you want to do. It has a nice long zoom (for plane spotting) yet will also handle wide-angle landscapes. And it has Wi-Fi and a large 3" LCD display. Go for it.

The L840, and super-zoom cameras like it, are well suited for being able to zoom in on distant objects like planes. Just be aware that they have 1/2.3" sensors, which is the smallest type available today. And with that small sensor comes very small pixels which have very poor dynamic range and produce a lot of noise. The is especially important to you because many, if not almost all, of your shots will include the blue sky. Solid colored areas like blue sky show noise the most. Therefore, you're going to be needing a very good photo editing program such as Lightroom to remove the noise from your images.

Here's a review of the L840 with sample photos. If the image quality is good enough for you, then the camera should be fine. http://www.photographyblog.com/reviews/nikon_coolpix_l840_review
Personally, I'd choose a bridge camera with as large of a sensor that I could find, such as any of these 1" format cameras: http://www.bhphotovideo.com/...4050180532

The 1" sensor will produce significantly better image quality than what a 1/2.3" sensor can.

Another option is to get a mirrorless camera in the Micro 4/3 format. With an even larger sensor, you now have the ability to capture more detail, even more dynamic range, with much less noise. Basically this equates to much better image quality and much less time spent in front of a computer fixing your images. The larger sensor will require larger lenses and therefore you will not have the option of having an all-in-one lens that zooms from wide to super telephoto. However, that's okay, because all you need for plane spotting a is a telephoto zoom. Tele zooms for micro 4/3 top off at 300mm which is the equivalent of 600mm in 35mm format. In contrast, the zoom in the L840 is the equivalent of a 23-855mm lens in 35mm format. However the lens alone will cost about twice as much as the entire L840.

In the end you get what you pay for. L840 is cheap but does the job. A micro 4/3 will have significantly better image quality, focusing speed, handling characteristics (all enable you to get the shot), but you're looking at around $1,000 for a body and a lens that does what you need it to do. Panasonic and Olympus both make very good M43 bodies.

Of all the P&S cameras, maybe the Nikon P900 would work the best for plane spotting. It has an 83x optical zoom. Of course you will have to use a tripod when using it at its longest focal length (add at least another $100 to your budget)

Where are the planes you're intending to photograph? An airport? Flying? What sorts of planes? Light planes, commercial planes or any?

This camera will work but you may need some better exposure control than it seems to offer (scene modes). Photographing aircraft can be tricky and cameras can be confused by white aircraft or the sky behind the aircraft so you may end up with under or overexposed photos.

As said by Frank, with the small sensors this camera has the photos won't have the greatest quality and the very wide zoom range tends to mean that there are a lot of optical compromises. This is likely to mean that, at higher zoom settings you'll lose some of the finer details on aircraft, e.g. Small text, the registration.