The naval forces kerplow the beach with their big guns. Then four or five lines of bombers - "fingers" - approach from north to south to bomb the beach in four or five spots on the 5.9-kilometre Omaha Beach, from the water to a bit inland. This would be a barrage of thunderous explosions, with much wider shock waves.

This is extra speculative because during the actual D-Day the navy wanted to avoid having bombs dumped on them, so they forced the bombers to delay releasing their bombs. As a result the beach was (arguably) missed completely, one of the reasons the Omaha Beach landing went so badly.

Flying right behind each finger of bombers come lines of C-47 Skytrain planes carrying paratroopers. There would be no issue with paratroopers landing in the wrong spot or at the wrong time, at least relative to the bombers. Would they fly at different heights?

Are paratroopers available? I suspect all the U.S. paratroopers were used for the drops around Utah Beach. As for the Brits, some were not used on D-Day. They were eventually dumped into the failed Arnhem offensive ("a bridge too far"). There is also the issue of aircraft availability.

I don't believe dropping paratroopers into an area immediately after it was bombed has ever been done. It would be smoky. Heat goes up. Dropping on a fortified area had been done, successfully, by Germans at Fort Eben-Emael in 1940.

Following behind the paratroopers come the landing craft. The paratroopers are dealing with the fortified positions and opening up a path inland, while the troops coming in landing craft reinforce the vulnerable paratroopers, after working through barbed wire and mines. If the landing troops and the paratroopers don't connect they would both be in serious trouble.

It's nice to picture paratroopers landing right on top of the fortified positions. However, while I'm not an expert on parachute landings I suspect people in planes would err on the side of not dropping people in the ocean, and they would drop in a comfortable field, sort themselves out, then move north in good order (and not seasick). Between the thunderous, battering bombardment, agressive paratroopers moving toward them from an awkward direction and a horizon full of ships sending landing craft toward them from the opposite direction, I'm sure the defenders - not as numerous as you think - would be dealt with and a safe path would be opened up.

The advantage of this fingers approach is that German defensive positions could be attacked, not head on but from the more vulnerable sides and rear by troops that had moved off the beach. Also some battlefield depth would be achieved within hours minutes.

The way I see it, these parachute drops would be a bit different than the ones that actually happened. It would not take place during the black of night but at 6:30 a.m.. You would be looking for the border of ocean and land, not a remote field. Since the planes are not going deep inland they would not face as many anti-aircraft guns. Would paratroopers be eaten up by anti-aircraft fire?
 
 
 
 

During the actual landing at Omaha Beach the first wave was massacred, and subsequent waves were piled up in deadly chaos. With this new approach, fingers combined with waves of troops landing on the length of Omaha Beach, the first wave would be massacred, and subsequent waves would be piled up in deadly chaos, although things would get progressively better. So why not have troops land safely only in secured beach areas? There are four reasons not to do this:

1) The fustest with the mostest. Forget the beach battles. The Normandy campaign as a whole was a story of who could bring more forces to the battlefield faster than their opponent. Keep sending bodies moving south, alive or whatever, in a conveyer belt of wave after wave. Put yourself in the shoes of a defending German commander. Having troops land in secured areas means that these secured areas could be gradually expanded, but notice the word "gradually". You have to secure the draws so that tanks and other vehicles can move off the beach.

2) Concentration of fire. German artillery was presited for areas of Omaha Beach. An artillery observer just had to say a code word like "Elefant" and artillery fire from different sources would then be concentrated for a period of time, say, midway from the water's edge to the seawall on a specific section of the beach. There could also be concentration of fire in the approach to the beach.

3) Landing in certain spots could be messy. Much can go wrong already, but with fingers in random places people would have to improvise who goes where when on the fly (including navy men removing obstacles). Might the landing craft arrive in the wrong spot - which actually happened - or would navigation be easy?

4) Having troops land on the length of the beach would give an early boost to rolling up the flank as the defenders would be attacked from multiple sides.
 
 
 
 

With the clean fingers plan, troops would only land in the fingers areas. Ram, jam troops in those areas. Ships could still batter the non-finger shoreline so that gunners and artillery observers and anyone else in the area are having a bad day. This would go on for, I don't know, 15-20 minutes, as long as you can determine what you are shooting at. Eventually the secured beach areas would expand. Flares might be useful.

The disadvantages of this plan have been listed above. But consider this: You know how in Saving Private Ryan the troops were massacred by (among other things) machine guns shooting north at them? Picture all the troops landing at Omaha Beach and none of them have to face machine guns shooting north at them.
 
 
 
 

So there is the paratrooper option, the integrated fire support (see the Stuff page) and there is the real world option. The real world option is just a little tweaking of the existing plan they had and its execution.
 
 

Before the actual D-Day navy people forced the bombers to wait a few seconds before releasing their bombs, so that bombs would not be dropped on the navy. As a result the bombers (arguably) missed the beach completely.

So if there was no delay before dropping the bombs, the beach could have been plastered. The bombardment was intended to bash not just the machine gun pillboxes but also the artillery.

Before the invasion the British had an excercise. The weather was challenging, and the duplex drive tanks could not handle that. As a result, during D-Day the British released their duplex drive Sherman tanks relatively close to the beach. American forces released their duplex drive tanks relatively far from the beach. As a result, most of the sank in the choppy waves.

If the American tanks are released close to the beach, the troops coming ashore would have their firepower and armour to help them get off the beach. This is not quite a panacea. Some tanks would still sink, and they would not arrive at the same time as the troops. Once they come to shore they could and would be shot at by anti-tank weapons firing down the length of the beach, with not a lot of manoeuvre options.

During the actual D-Day on Omaha the landed troops were pinned down and massacred for hours. Eventually destroyers came very close to the beach, even almost scraping the bottom, to pound targets. Coming close meant that visibility in that smoky environment was improved. There was some wrangling to allow the destroyers to do this. The guns on a destroyer are powerful, and this certainly helped the troops to make it off the beach.

For a tweaked D-Day plan, there should at least be plans made for the possible use of destroyers for close support.

I would provide a tarp for the landing craft to prevent them being waterlogged. I would also provide ginger to the soldiers to deal with seasickness.