The book of Daniel offers a rare glimpse into the events that can occur with angels in the unseen spirit-based realm. This short article will show that they do indeed spiritually fight. The battles between righteous spirits who obey God and demonic or evil angels have, and will, affect world history and the destiny of nations.
An example
Our first fight example revolves around Daniel, who had been fasting and mourning for three full weeks (Daniel 10:1 - 3). He then sees a vision of one of God's angels. The angelic being states that God sent him the moment he began to humble himself and pray (verse 12).
Why, however, did one of the most powerful spirit beings ever created (likely the archangel Gabriel, see 8:16 and 9:21) take a few weeks to spiritually travel to Daniel? What caused such a great delay?

Gabriel, who normally would have delivered God's message the moment after he got it, was unable, of himself, to get past the "prince of the kingdom of Persia" (Daniel 10:13)! It took another of God's powerful angels, whose name is Michael, to come and help him fight his way through to deliver his message.
Since Gabriel was sent directly by God, whoever hindered him from completing his mission was almost certainly an enemy of righteousness. Could the evil "prince of the kingdom of Persia" (10:13), who almost stopped Gabriel's journey, be a powerful human being? The short answer is NO.
Human beings have no power, of themselves, to fight even the weakest of spirit beings (Hebrews 1:7). A small group of the lowest of angels could kill countless human beings at will. Flesh and blood beings are completely helpless before the power of spirit-composed beings (Mark 16:17, Luke 9:1).
Angelic power
When God wanted to rescue Jerusalem from being attacked by Sennacherib, he needed only one of his angels to kill 185,000 Assyrian warriors in a single night (Isaiah 37:36). This means that while a human prince could not have resisted a righteous spirit, it must have been a spirit who was evil and willing to fight a righteous and powerful being making his way to Daniel.
The use of a reference "the prince of the kingdom of Persia" found in Daniel 10:13 symbolizes a powerful demonic spirit. This symbolism is sometimes used in the Bible (see Ezekiel 28:12 - 19, Isaiah 14:4, 12 - 15). Although nominally these texts in Ezekiel and Isaiah appear addressed to mere human kings, they are actually about a powerful, ambitious, and vain spirit who rules over all the rebellious spirits. No ordinary human king, for example, could have been in the Garden of Eden (compare Genesis 3:22 - 24 to Ezekiel 28:13).
Note that Gabriel did not say that just anyone fought him to try to stop his message from reaching Daniel. The evil spirit who opposed him is the "prince" of Persia and not Babylon or some other nation. God seems to have assigned angels different principalities and powers (see Romans 8:38, Ephesians 3:10, Colossians 1:16, 2:15).
Authority of angels
For example, in regard to the authority given to certain spirits, the archangel Michael is called a prince of Israel (Daniel 10:21) and a chief prince (verse 13). In like fashion, the devil has assigned certain of his evil accomplices positions of authority over earthly kingdoms (Ephesians 6:12).
What happened to Gabriel was that when he got near Persia he met with resistance from, and no doubt had to fight, an evil angel (with lesser demonic powers under his control?) given authority to influence the affairs of the world power.
After an unsuccessful twenty-one day attempt to overcome the demon controlling access to Persia, Michael came and helped Gabriel 'break through' to deliver his message. All this makes one wonder how many angels fight on a daily basis.