More to the point, Spain was a neutral in WWII, not an ally.
No, that's not more to the point - rather the opposite.
Not only were Marshall Plan aid given to countries that had been enemies (like Germany and Italy), but also to countries that had been neutral (like Switzerland and Sweden).
But the aid was very disproportionately handed out, with countries like Ireland, Portugal and Scandinavia receiving little, while countries with more industry getting the majority of the aid. To make matters worse, the countries that received the least generally also received most of the aid as loans, and not grants;
The UK received around $3.3 billion, of which around 90% were grants. Ireland received around $130-140 million, of which around 90% were loans, not grants.
More than anything, it was a device for tying European industry to American exports. The biggest profiteers were American (and later Canadian) companies who were paid for their exports through Marshall Plan funds, as part of the condition for receiving aid.