Relations with other Martial Arts...
Aiki (as distinct from Aikido) is the origin of all martial arts. This is what the Founder of Aikido wished to express when he named his art takemusuaiki.
However, it is important to note that the primordial nature of Aiki doesn't imply that Aikido is the best martial art, but only that it is one way towards aiki. Being able to develop the multiple facets of Aikido requires one to integrate the principle of Aiki.
Aiki consists in uniting oneself with the ki of the heavens and the earth. Aiki is not exclusive to budo but is part of all human activity. Applying the principle of Aikido to events will help us understand them better; acting in accord with this principle will make our actions easier.
This principle applies to daily life, to social relations and to modern science.
Bujutsu and Budo were created by men who lived on the edge of life and death. Driven by an unshakable will, such men built up layers of experience, invoked the gods and prayed beneath waterfalls.
Bujutsu and Budo are not merely techniques. Their value comes from using asceticism to go beyond technique. The techniques originated from the specific circumstances of their creator's life: the place, the era, the human situation. Thus if you are given a chance, widen your horizons and practice or watch techniques anytime an occasion presents itself.
Compare and see what you can integrate in your own practice of Aikido. But beware; the idea is not to copy the other arts nor to mix them together!