Vuetify Autocomplete dropdown not working - vue.js

Question

I am using vuetify autocomplete component in my nuxt project. its not working as expected. problem is when i start typing it fetches data using api but it doesn't show me results in dropdown, but once i click outside input box and then again focus on search box, then it shows the dropdown. but i want to see the results on every key press.
here is the code so far.
<v-autocomplete v-model="pickupairport" name="pickupairport" :items="airports" :loading="isLoading" :search-input.sync="aptsearch" chips clearable hide-details hide-selected label="Search for a airport..." solo>
<template v-slot:no-data>
<v-list-item>
<v-list-item-title>
Search for your favorite
<strong>Destinations</strong>
</v-list-item-title>
</v-list-item>
</template>
<template v-slot:selection="{ attr, on, item, selected }">
<v-chip v-bind="attr" :input-value="selected" color="blue-grey" class="white--text" v-on="on">
<v-icon left>
mdi-bitcoin
</v-icon>
<span v-text="item.name"></span>
</v-chip>
</template>
<template v-slot:item="{ item }">
<v-list-item-avatar color="indigo" class="text-h5 font-weight-light white--text">
{{ item.name.charAt(0) }}
</v-list-item-avatar>
<v-list-item-content>
<v-list-item-title v-text="item.name"></v-list-item-title>
<v-list-item-subtitle>{{item.cityName}}, {{item.countryName}}</v-list-item-subtitle>
</v-list-item-content>
<v-list-item-action>
<v-icon>fa-airports</v-icon>
</v-list-item-action>
</template>
</v-autocomplete>
this is script part
export default {
data() {
return {
aptsearch: null,
items: [],
model: null,
tab: null,
pickupairport: '',
airports: [],
isLoading: false,
uuid: this.$uuid.v4(),
}
},
watch: {
model(val) {
if (val != null) this.tab = 0
else this.tab = null
},
aptsearch(val) {
// Items have already been loaded
if (this.items.length > 0) return
this.isLoading = true
// Lazily load input items
fetch(`${process.env.EXPRESS_API_URL}/airports/find`, {
method: "post",
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
body: JSON.stringify({
aptsearchkey: this.aptsearch
})
})
.then(response => {
return response.json();
})
.then((data) => {
this.airports = []
data.forEach((item) => this.airports.push(item))
})
.catch(err => {
console.log(err)
})
.finally(() => (this.isLoading = false))
},
}