The RAF employed the Hurricane Mk IID and IV with 40mm Vickers 'S' guns in the desert in 1942, and these were accurate and effective, but the Hurricanes were highly vulnerable to ground fire and were withdrawn from European service prior to D-Day. The RAF turned instead to 60lb RP-3 rocket projectiles, primarily carried by Typhoons, as a more versatile weapon, packing a greater punch against the increasing armour of German tanks and not encumbering aircraft once fired. They were not very accuracte, though; Ian Gooderson's thesis Allied Close Air Support 1943-1945 includes a section "Allied Fighter-Bombers Versus German Armoured Forces: Myths and Realities" that outlines a test carried out by eight Typhoons with eight rockets each against a captured Panther tank. With no return fire, against a clearly identified and stationary target only three of the 64 rockets hit the target.

Gooderson then examines several examples from the Normandy campaign in which RAF Typhoons and USAAF Thunderbolts were credited with large numbers of German tank kills, referring to reports by British Army Operational Research Sections (ORS) that investigated battlefields and attempted to classify actual losses and causes. In all cases armoured vehicle losses positively identified as being caused by air attack were lower than those that were abandoned or destroyed by their own crews. At the Falaise Pocket in August 1944, for example, the 2nd Tactical Air Force and 9th Air Force claimed over 400 armoured targets destroyed; the ORS examined three areas and classified 35 tanks and SP guns as aircraft kills, 16 as ground kills and 304 abandoned or destroyed by their crew.

In terms of direct effectiveness against tanks, then, fighter-bombers had a rather poor record; the rockets were inaccurate and required a direct hit to be effective. To soft-skin motor transport, though, they were far more dangerous; several hundred lorries, cars and motorcycles in the Falaise Pocket were destroyed by rockets, bombs and aircraft cannon and machine guns. By destroying supply vehicles tanks were starved of fuel and ammunition, in mixed columns roads were blocked, contributory factors in the tanks being abandoned. The psychological effect upon crew could also be considerable, especially inexperienced soldiers; from questioning prisoners of war:

"The experienced crews stated that when attacked from the air they remained in their tanks which had no more than superficial damage (cannon strikes or near misses from bombs). They had great difficulty in preventing the inexperienced men from baling out when our aircraft attacked."

Gooderson thus concludes that close air support might not always have been successful in destroying targets, but was highly effective at neutralising them.

I assume you are mostly talking about Allied fighter-bombers attacking German vehicles on the west front so I will focus my answer on that.

The effects of the anti-tank capabilities of fighter-bombers were overstated shortly after the war. This was mostly due to heavy over claiming of the pilots. As a pilot it was extremely difficult to assess the damage their weapons did to the vehicle they targeted, even bombs landing close to a tank maybe didn't even damage the tank significantly. This resulted in massive kill claims of Allied pilots which then resulted in a warped perception of the effectiveness of aircrafts acting in anti tank duty. The pilots while being in a very high-pressure situation had only a very short amount of time to evaluate the possible damage. Imagine a pilot strafing a German tank and shooting his rockets which all land next to or even on the tank, he will obviously assume the tank is destroyed but in all likelihood, his best chance on a kill would be the German crew bailing out due to fear. Add on this that regardless of the status of tank the area around the tank was smoking/burning due to the impact of the bombs. While doing his run he was likely under fire from AA it's easy to see how the high number of kill claims developed.

The most well-known research about this is the data presented by an Allied research group studying German tank wrecks all over Normandy and the Bulge to a smaller degreee. Those studies got more and more attention in the recent decades which prompted many historians to drastically change their views on dive bombers during WW2. The group "No.2 operational research section" was raised to analyse combat data and part of it was investigating fighter-bomber effects on enemy tanks.

In my opinion, the revisionism about this issue went too far and now underestimates the impact of air power on enemy AFVs. Checking the reports of operational research group shows beyond doubt that at least Western Allied kill claims on tanks were massively exaggerated but that doesn't mean aircraft had no significant impact on the tank force of the enemy on the contrary.

The Allied aircraft often were attributed with stopping entire German advances on their own, a prime example for this would be Unternehmen Lüttich. This view of air power was incorrect and aircraft on their own were not able to destroy an attacking tank force but their impact was certainly a major part in defeating the fighting capabilities of German armoured units. About 480 claims for either destroyed or damaged AFVs were filled but only 33 were found to be destroyed by air. Those findings resulted in two things first, it showed clearly that reports of Allied airpower annihilating German attacks on their own were overexaggerated but secondly, it took credit away from the actual results. 33 tanks destroyed on its own is already significant but looked disappointing compared to the initial claims and the earlier perception.

The focus on tank kills took also attention away from other effects Allied air power had on the Germans. The Allied airpower was able to disrupt support lines to German armor which dried up especially the supply of fuel and rendered German forces often ineffective. A good example for this would be the Battle of the Bulge when German Panzer divisions after deep penetration stopped getting supplies when the skies cleared and the thin supply lines got ravaged by fighter bombers. This is only one of the many effects Allied air power had on their enemies. Most of the relevant effects are not so flashy and didn't get much attention in books. If you ,for example, read the logs and histories of German divisions you will often find how heavy equipment or fuel trucks only operated during night. Even without a plane at the sky, the Germans were affected and their fighting power was reduced.

Another underestimated effect of fighter-bombers was their impact on the accompanying infantry. Like in most armies German tanks tried to operate closely with their infantry, a sky full of fighter-bombers was a terrifying view for infantry and often forced them to seek cover which left the tanks exposed and without a major "combined-arms" part. You might notice that I listed several examples which didn't even include the direct destruction of the German tank but still had a noticeable impact.

While the image of fighter-bombers wiping out entire German tank battalions is fiction and not based on reality the fighter-bomber units were still a potent option for destroying German tanks directly, not because the fighter-bomber was particularly effective at it but because the Allied had enough of them. Fighter bombers inflicted significant casualties on the German tank forces. Depending on the source you find estimates of up to 10% German tank losses were due to air. Here it might be worth to add that the fighter-bombers in WW2 were not really designed to take on tanks, designated tank hunting aircraft were mostly developed after WW2 and aircraft used for this role were more or less pressed into this role out of necessity. A notable exception to this would be the German Hs-129 which was designed with the role as a designated ground attacker in mind, to my knowledge it is also the only aircraft credited with stopping an armoured attack on its own. This aircraft was equipped with a 75mm anti-tank gun which allowed the aircraft to destroy a tank with direct hits on its vulnerable top. Allied fighter-bombers were reliant on a hit with 500kg bomb or their rockets which was most certainly harder to achieve. Their main armament was rarely able to inflict damage. But designated tank hunter aircraft were in their infancy during WW2 even the Hs 129 had a hard time. One of the major disadvantages was that such aircraft were vulnerable to interceptors and this problem was never fully resolved even after WW2. While the Allies had air supremacy which kinda negated this weakness more than 1500 ground attackers were lost in Normandy alone. As a side note it might be interesting to know that some of the most senior commanders of the German forces were taken out by fighter bombers most notably Fieldmarshal Erwin Rommel.

While not part of your initial question I want to add that at times the strategic air force of the Allies had a massive effect on the German tank forces. A major example would be the opening bombardment during Operation Goodwood which put out of action the better part of an entire fresh German heavy tank battalion and seriously damaged the Panzer IV battalion of the 21st Panzer. All in all the bombardment either destroyed or impaired the operations of up to 50 tanks. Another noticeable side effect of such massive bombardments was that tanks had trouble maneuvering around the craters created by the bombs.