Honestly you absolutely need to grab the Sony WH-1000XM4 Wireless Noise Canceling Headphones before you hop on that plane! They are literally the gold standard for travel and i have used mine on dozens of long hauls. Even though there is a newer model out, the XM4 is way better for international flights because they actually fold up into a small case. The newer ones just lay flat which takes up way too much room in a carry-on imho. Here is why they are a total game changer for a London flight:

• The noise canceling is legendary. It blocks out that annoying engine drone so well you actually forget youre flying.
• Battery life is massive. You get 30 hours on a single charge which is plenty for the whole trip and back.
• Atmospheric Pressure Optimization. This is the secret sauce! You can calibrate them for the cabin pressure so the audio stays perfect while you are cruising. I love mine to death and honestly wont fly without them. If you see them at the airport for under $300 just snag them immediately. The ear pads are incredibly plush so your head wont feel squeezed after six or seven hours... such a lifesaver for sleeping! Seriously dont bother with the cheaper models like the CH series if you have the cash, the noise canceling just isnt on the same level when you are stuck near the engines!

To add to the point above: if you want the absolute latest tech and can find a deal at the duty-free shop, the Sony WH-1000XM5 Wireless Noise Canceling Headphones are legendary! I have used every single version of these over the years and the new design is so light it feels like you arent even wearing anything, which is a total must for those 8+ hour flights. The noise canceling is on another level... it totally deletes the sound of the engines. Love it! Quick tip for you: definitely check out the Sony WF-1000XM5 Wireless Noise Canceling Earbuds if you are a side sleeper! I honestly prefer them for red-eyes because I can lean my head against the window without the bulk of a headband getting in the way. They use these special foam tips that basically act like earplugs while playing your music. Fantastic stuff and they should be right around your $300 budget tho prices at airports can be weird. Just make sure you install the Sony Headphones Connect app on your phone before you leave. You can use it to set up the Speak-to-Chat feature so your music pauses when you talk to the flight attendants. Its so helpful! Have a safe flight to London... you're gonna have such a blast there!! If you need anything else or have questions about the settings just shout. Im so excited for you!