There are many sources of noise inside an airliner, such as:

• Jet engines
• Wind noise
• Mechanical noises from air conditioners/cabin pressurization equipment
• In-flight Entertainment systems
• Passengers talking
• Babies carying
• …etc

There is no single solution to eliminate all of the noises, and with tinnitus being a “perception” of sound instead of real sound, it is even harder to find a solution. Some of the common solutions for normal noisy environments are:

• Noise canceling head-sets. These typically work on a principle of anti-noise, by generating a equivalent noise to the ambient noise, but at a inverted phase, the effect is to cancel out the ambient noise. This type of device actually makes it easier to hear other sounds, since the anti-noise works most effectively against consistent noise such as the humming of jet engines.
• Ear-plugs, often made from foam or latex, and block noise in the ear canal mechanically.
• Cushion type headphones, large and bulky, but provides a noise barrier by completely covering the ears.
• Gel-filled ear-bud headphones, another mechanical means to block noise with a gel cushion that conforms to the ear canal.

We do not have noise level readings of different areas of an airliners, but personal experience seem to indicate that noise levels are not significantly different in different areas of a plane. There might be a slight different in the areas farther ahead of the engines, due to the jet exhaust flow toward the back of the plane.