The witness said the UFO crossed the highway 100 to 300 metres above ground and described seeing a "glow" and "bubble" at the front of the object.
Hansen, who started the sightings network in 2000 after experiencing a UFO event in Hawke's Bay, said over the years, reports have been submitted by scientists, truck drivers, farmers, pilots and police for a number of reasons.
"People report sightings for any number of reasons including curiosity, enthusiasm, wonderment, fear, confusion and shaken religious or worldviews," he said.
"Often they're easy to explain, but just as many descriptions from witnesses defy our current understanding of physics."
The second incident occurred near an equestrian grounds on the outskirts of Hastings at 6.45pm.
The mother and daughter witnesses spotted a set of red and green lights at low altitude in the sky over several minutes.
They described the movement as "hovering" behind a set of trees, before moving parallel over farmlands and then towards Flaxmere.
The following day, the Bridge Pa Aerodrome told the witnesses a light aircraft was conducting formation flying the day before. But witnesses said the object they observed was low, slow, silent and had an unconventional light configuration that indicated a rectangular or elongated shape.
The final unusual sighting, at about 6.50pm, also occurred near an equestrian park in Hastings.
The witness and her children saw about 12 red and green airborne lights approaching in two rows, outlining a "massive" rectangular, narrow shape.
MetService meteorologist Lewis Ferris said the recent sightings are likely to be lenticular cloud, which can take on shape of a UFO.
Ferris said the westerly winds flowing across the region on April 24 were "perfect for forming lenticular clouds".
"This is very common around the Takapau area," he said.
Hansen said a "UFO Flap" – a cluster of sightings in a defined period of time, usually within a certain area – is common.
"Characteristics such as extreme propulsion within seconds, acute turns, silent movement, no visible wings, tail or propulsion and lack of sonic booms tell us that for at least some events, we are dealing with some advanced technology."
Hansen said a "terrifying" day-time sighting of unusual lights that "behaved in a way that discounted aircraft" on SH50 in 1975 sparked her UFO interest.
"The lights descended over my car. With such blinding brightness the road and all surroundings could not be seen, and the car rolled to a stop," she said.
Hansen said Hawke's Bay's most notable UFO sighting was at the Waipukurau Aerodrome in 1969.
