One Can Summon Angels...

Going back to the succubus and antipaladin stuff I mentioned earlier, Uncle Khasim in the Pathfinder thread pointed out that the wording for Summon Monster not only forbids summoned monsters from using their own summoning spells, but also from using any teleportation or planar travel abilities. So RAW, a succubus probably can't teleport your party around (though the succubus still can fly you across obstacles).

Edit: I have since corrected this on the previous one

When it comes to summoning monsters, perhaps the only thing equal or superior to summoning evil outsiders is summoning good ones, because not only do they have similar spell-like abilities, they also cast spells.

The Empyreal Knight gains the ability to use Summon Monster a number of times per day equal to the paladin's charisma modifier, scaling the ability to the paladin's level, which can be used to summon celestial creatures, archons, or angels, though the spell list is short on the latter two until high levels. Sadly, this ability is not as good as the Summoner, whose ability can be used more often, lasts longer and can be used to summon Azata, the Chaotic Good outsiders who show up more often in the mid-levels.

On the bright side, the Empyreal Knight still has a mount like a regular paladin, only this one scales faster. At 12th level, the mount gains a fly speed equal to twice its land speed at good maneuverability (or improves to this speed/maneuverability if it already has a fly speed), which means you can ride into battle on a winged T-Rex.

The more interesting paladin archetype is the Sacred Servant, which at 8th level gets the ability to cast Planar Ally free of charge once per week, with the ability scaling with level. Normally, Planar Ally is balanced by cost- keeping a creature around for a small task that takes only a few minutes costs the least, while it cost ten times more if you want to keep someone around for a few days. But since you don't have to pay for the service, there's no reason not to splurge on the 1 day/caster level version. Every seven days you can summon a creature for a number of days equal to your caster level, starting at 8, which means that at higher levels you can keep an ally around for two or more weeks while your ability recharges.

True, the ability says that you don't have to pay "for reasonable tasks", but you're a paladin. Whistle up an angel and say "You and I are both exalted champions of the holy power of our god of light. Let us engage in jolly cooperation and go shove our golden boots up the asses of evil for the next week or so. You down?" then bump fists in the freeze-frame.

As I mentioned earlier, Summon Monster comes with the restriction that your summons can't summon other monsters, teleport or engage in planar travel. Planar Ally is not a summoning spell, it is a calling spell which brings the entire creature into your world and is thus under no such restrictions. Several major good outsiders come with greater teleport as a spell-like ability, so there's nothing stopping you from using them as celestial taxis.

At level 8, you're using lesser planar ally, which is capped at summoning outsiders with 6 hit dice. Probably one of the better options is the hound archon, which aside from being a decent fighter when you have the right spell support also has greater teleport at-will, which means you can give your party the ability to travel anywhere in the world before your team wizard can even learn a regular limited version of teleport.

At level 12, you upgrade to regular planar ally, capped at summoning 12 hit dice worth of outsiders. The standard options are kind of dull, but the coatl is a decent enough flying wizard snake if you don't feel like summoning more hound archons. Sadly, Paizo upped the hit dice on the Trumpet Archon from 12 to 14, preventing you from being a 12th level character who could whistle up a 14th level cleric (as you could in 3e, if you were willing to pay for it). You can still summon a Shield Archon to teleport around and also tank for you and your team, or a movanic deva to fight and restore you.

At level 16, you upgrade to greater planar ally, capped at summoning 18 hit dice worth of outsiders. This is the point where shit officially derails. Right from the word go, you can summon a Planetar, and thus be a 16th level paladin who can summon a 16th level cleric. In fact, since you can use this ability once per week to summon something for 16 days, you can have two 16th level clerics with you at all times, or three for two days every week. But these aren't 16th level clerics, they're better. True, they don't have access to the ability to channel positive energy or domain boosts, and they aren't proficient with any armor. But you can cast mage armor on them or give them magic items, and they have better hit points, attack bonuses, and ability scores, plus a protective aura that shields them and any allies from spells and the attacks of evil. They have their own pile of spell-like abilities, including the ability to dispel magic, curses, diseases and fatigue at-will, raise the dead, damage and debilitate foes, even shatter buildings or remove permanent negative levels. They can also disguise themselves as regular humanoids, speak with any creature living or dead, and see through illusions, magical disguises, lies, evil and even basic traps. This is the stuff they can do without casting their 16 levels of spells. If they do start using their spells, well... they can summon more angels. Or maybe cast greater planar ally to bring in their own buddies.

Sadly, planetars can't teleport, though they can cast plane shift. But hey, you can also summon a trumpet archon, who can teleport at-will and also cast spells as a 14th level cleric. Pity Star Archons have 19 hit dice instead of 18, putting them just out of reach.

Of course, recall that the Sacred Servant's planar ally ability just targets outsiders, and unlike the Empyreal Knight it has no further restrictions other than the fact that the paladin can't use it to summon creatures with the chaotic or evil subtypes due to the rules of spellcasting (though if you can be a neutral good paladin then you can summon chaotic outsiders). Thus, not only can you summon things such as the neutral good agathions like Cetaceals (who can also teleport), you don't even have to have stick to good outsiders.

A Shaitan is a lawful neutral earth genie with a pile of abilities that deal with earth. A shaitan pasha has 18 hit dice and can be summoned with Greater Planar Ally. Among its powers is the ability to grant three wishes... per day. Two or three of these guys out at once and you can do damn near anything, including giving you and your buddies a +5 bonus to every stat just because.

As long as you're in the market for having your GM throw the rulebook at your head, remember that not only can you call for outsiders, but you can ask for specific ones. An aasimar is an outsider, and all of its six to eighteen hit dice can be class levels, so your level 16 paladin can request a level 18 aasimar cleric or wizard. If you want to get even more ridiculous, half-celestial is a template that can be applied to almost any creature, turning it into an outsider and increasing its power without actually giving it any extra hit dice. Ask for half-celestial level orc barbarians, or maybe half-celestial dragons.

Your Angel Summoner may not be able to summon a horde of celestial super-beings at-will, but you can certainly make one hell of a show at it.