Car sounding like an airplane on the highway - 1996 Honda Civic

When the engine sounds like an airplane, the most common problem is your fan clutch. It's not dis-engaging, all of us have had that problem OR will at some point with this vehicle platform. Replace the fan clutch.

If it sounds like a jet taking off then it's most likely some rush of air so where/how does air under pressure come from? Well, it comes from your exhaust but you said that's been replaced. Could be a cylinder head gasket in a engine but you would have felt a lose of power if that was the problem.
Is it a bearing that just sounds like an air sound? As I've suggested with other people...have someone follow you, then pull up along side of you on both sides and see if they can hear/isolate where the sound is coming from.

Sometimes when you're driving it's hard to hear exactly where the sound is coming from because well....you're driving!
So having two people in another car riding along side of you on the highway or unpopulated back road can hear it better.

Just remember to do it safely...you are on the road after all but if you hear it at 40...you should be able to hear it loud and clear at 55 or 65 or whatever the speed limit is.

Going too slow on the highway is dangerous too so obey the speed limits.

Sounds like the engine cooling fan clutch is defective. If it remains locked up the noise does sound like an airplane.

blown exhaust or loose air intake get these looked at first.Is it an auto ? as you can get a roar from a faulty auto box but start with the easy stuff

bad cv on passenger axel shaft if it has IFS if it has solid axle check the axle joint

You had to use force because the splines are no longer aligned. The noises are made by the hub bearings, it's worn out and you must replace them. If the bearing is severely worn out it would also explain why the splines are no longer aligned.

Check the flow of exhaust out of the tailpipe. If flow is not good, then the catalytic converter, if so equipped, could be plugged up causing the 'jet' sound you hear on acceleration.

Hello young lass,
I'm always glad to help out a damsel in distress.
I will need a bit more info though. Like can you give a better example of the sound and where exactly is the noise coming from. I mean the engine area or the rear of the car. Does it make the sound when parked when you rev the motor up? Fill in the blanks for me dear and I will be waiting here to offer you my best, Razzy

exhaust gaket leaking or a loose joint or both

sounds like it's your muffler, does it constantly make this sounds, or only when you accelerate? I